automatic transmission DODGE RAM 2001 Service Workshop Manual

INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the instrument cluster to the instru-
ment panel.
(2) If the vehicle is equipped with an automatic
transmission, position the gear selector indicator onto
the back of the cluster housing (Fig. 3).
(3) If the vehicle is equipped with an automatic
transmission, install and tighten the two screws that
secure the gear selector indicator mechanism to the
back of the cluster housing. Tighten the screws to 2.2
N´m (20 in. lbs.).
(4) Align the instrument cluster with the cluster
opening in the instrument panel and push the cluster
firmly and evenly into place. The instrument panel
wire harness has two self-docking connectors that
will be automatically aligned with, and connected to
the instrument cluster connector receptacles when
the cluster is properly installed in the instrument
panel.
(5) Install and tighten the four screws that secure
the instrument cluster to the instrument panel (Fig.
2). Tighten the screws to 2.2 N´m (20 in. lbs.).
(6) Reinstall the cluster bezel onto the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - INSTALLATION).
(7) If the vehicle is equipped with an automatic
transmission, confirm proper operation of the gear
selector indicator. Calibrate the indicator, if required.
(Refer to 19 - STEERING/COLUMN - INSTALLA-
TION).
(8) Reconnect the battery negative cable.
NOTE: Some of the indicators in this instrument
cluster are either programmable (upshift indicator)
or automatically configured (cruise, overdrive-off,
and transmission overtemp indicators) when the
cluster is connected to the vehicle electrical sys-
tem. This feature allows those indicator lamps to be
enabled or disabled for compatibility with certain
optional equipment. If a new instrument cluster is
being installed, use a DRBIIITscan tool to programthe instrument cluster with the proper vehicle
equipment option setting to enable and/or disable
the upshift indicator lamp. Refer to the appropriate
diagnostic information.
ABS INDICATOR
DESCRIPTION
An Antilock Brake System (ABS) indicator is stan-
dard equipment on all instrument clusters. This indi-
cator serves both the standard equipment Rear
Wheel Anti-Lock (RWAL) and optional equipment
4-Wheel Anti-Lock (4WAL) brake systems. The ABS
indicator is located near the lower edge of the instru-
ment cluster overlay, to the left of center. The ABS
indicator consists of a stencilled cutout of the Inter-
national Control and Display Symbol icon for ªFail-
ure of Anti-lock Braking Systemº in the opaque layer
of the instrument cluster overlay. The dark outer
layer of the overlay prevents the indicator from being
clearly visible when it is not illuminated. An amber
lens behind the cutout in the opaque layer of the
overlay causes the icon to appear in amber through
the translucent outer layer of the overlay when it is
illuminated from behind by a Light Emitting Diode
(LED) soldered onto the instrument cluster electronic
circuit board. The ABS indicator is serviced as a unit
with the instrument cluster.
OPERATION
The ABS indicator gives an indication to the vehi-
cle operator when the ABS system is faulty or inop-
erative. This indicator is controlled by a transistor on
the instrument cluster circuit board based upon clus-
ter programming and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Chrysler Collision Detection (CCD) data bus.
The ABS indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, the
LED will always be off when the ignition switch is in
any position except On or Start. The LED only illu-
minates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the ABS indicator for the following rea-
sons:
²Bulb Test- Each time the ignition switch is
turned to the On position the ABS indicator is illu-
minated by the cluster for about two seconds as a
bulb test.
²ABS Lamp-On Message- Each time the clus-
ter receives a lamp-on message from the CAB, the
8J - 14 INSTRUMENT CLUSTERBR/BE
INSTRUMENT CLUSTER (Continued)

Trouble Code (DTC) for any malfunction it detects.
Each time the airbag indicator fails to illuminate due
to an open or short in the cluster airbag indicator cir-
cuit, the cluster sends a message notifying the ACM
of the condition, the ACM will store a DTC, and the
cluster begins blinking the seat belt indicator. (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER/
SEATBELT INDICATOR - OPERATION). For proper
diagnosis of the airbag system, the ACM, the CCD
data bus, or the message inputs to the instrument
cluster that control the airbag indicator, a DRBIIIt
scan tool is required. Refer to the appropriate diag-
nostic information.
BRAKE/PARK BRAKE
INDICATOR
DESCRIPTION
A brake indicator is standard equipment on all
instrument clusters. The brake indicator is located
near the lower edge of the instrument cluster overlay,
to the right of center. The brake indicator consists of
a stenciled cutout of the word ªBRAKEº in the
opaque layer of the instrument cluster overlay. The
dark outer layer of the overlay prevents the indicator
from being clearly visible when it is not illuminated.
A red lens behind the cutout in the opaque layer of
the overlay causes the ªBRAKEº text to appear in
red through the translucent outer layer of the over-
lay when it is illuminated from behind by a Light
Emitting Diode (LED) soldered onto the instrument
cluster electronic circuit board. The brake indicator is
serviced as a unit with the instrument cluster.
OPERATION
The brake indicator gives an indication to the vehi-
cle operator when the parking brake is applied, or
when there are certain brake hydraulic system mal-
functions. This indicator is controlled by a transistor
on the instrument cluster circuit board based upon a
hard wired input to the instrument cluster, cluster
programming, and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Chrysler Collision Detection (CCD) data bus.
The brake indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, the
LED will always be off when the ignition switch is in
any position except On or Start. The LED only illu-
minates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the brake indicator for the following rea-
sons:²Bulb Test- Each time the ignition switch is
turned to the On position the brake indicator is illu-
minated by the instrument cluster for about four sec-
onds as a bulb test.
²Park Brake-On- If the park brake is applied
or not fully released with the ignition switch in the
On position, the brake indicator is illuminated solid.
The brake indicator will blink on and off repeatedly
when the park brake is applied or not fully released
and the ignition switch is in the On position if a
vehicle with an automatic transmission is not in
Park or Neutral, or if the engine is running on vehi-
cles with a manual transmission.
²Brake Lamp-On Message- Each time the
cluster receives a lamp-on message from the CAB,
the brake indicator will be illuminated. The indicator
remains illuminated until the cluster receives a
lamp-off message from the CAB, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Actuator Test- Each time the instrument clus-
ter is put through the actuator test, the brake indi-
cator will be turned on during the bulb check portion
of the test to confirm the functionality of the LED
and the cluster control circuitry.
The park brake switch on the park brake pedal
mechanism provides a hard wired ground input to
the instrument cluster circuitry through the park
brake switch sense circuit whenever the park brake
is applied or not fully released. The CAB continually
monitors the brake pressure switch on the brake
combination valve to determine if the pressures in
the two halves of the split brake hydraulic system
are unequal. The CAB then sends the proper lamp-on
or lamp-off messages to the instrument cluster. If the
CAB sends a lamp-on message after the bulb test, it
indicates that the CAB has detected a brake hydrau-
lic system malfunction and/or that the ABS system
has become inoperative. The CAB will store a Diag-
nostic Trouble Code (DTC) for any malfunction it
detects. The park brake switch input to the instru-
ment cluster can be diagnosed using conventional
diagnostic tools and methods. For proper diagnosis of
the antilock brake system, the CAB, the CCD data
bus, or the message inputs to the instrument cluster
that control the brake indicator, a DRBIIItscan tool
is required. Refer to the appropriate diagnostic infor-
mation.
DIAGNOSIS AND TESTING - BRAKE INDICATOR
The diagnosis found here addresses an inoperative
brake indicator condition. If the brake indicator
comes on or stays on with the ignition switch in the
On position and the park brake released, or comes on
while driving, the brake system must be diagnosed
and repaired prior to performing the following tests.
8J - 16 INSTRUMENT CLUSTERBR/BE
AIRBAG INDICATOR (Continued)

²More Than Full Percent Tank Full Message
- Each time the cluster receives a message from the
PCM indicating the percent tank full is more than
full, the gauge needle is moved to the far left (low)
end of the gauge scale and the low fuel indicator is
illuminated immediately. This message would indi-
cate that the fuel tank sender input to the PCM is an
open circuit.
²Message Failure- If the cluster fails to receive
a percent tank full message, it will hold the gauge
needle at the last indication until a new message is
received, or until the ignition switch is turned to the
Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept to several calibration points on the gauge scale
in a prescribed sequence in order to confirm the func-
tionality of the gauge and the cluster control cir-
cuitry.
The PCM continually monitors the fuel tank send-
ing unit, then sends the proper messages to the
instrument cluster. For further diagnosis of the fuel
gauge or the instrument cluster circuitry that con-
trols the gauge, (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the fuel tank sending unit,
the PCM, the CCD data bus, or the message inputs
to the instrument cluster that control the fuel gauge,
a DRBIIItscan tool is required. Refer to the appro-
priate diagnostic information.
GEAR SELECTOR INDICATOR
DESCRIPTION
A mechanical automatic transmission gear selector
indicator is standard factory-installed equipment on
this model, when it is also equipped with an optional
automatic transmission. The gear selector indicator
consists of a molded black plastic housing with inte-
gral mounting tabs that is secured to the back of the
instrument cluster housing with two screws. A face
plate on the indicator housing is visible through a
rectangular cutout in the lower right corner of the
instrument cluster overlay, just below the fuel gauge.
Vehicles with a manual transmission have a block-off
plate mounted to the back of the instrument cluster
behind this cutout in the overlay, in place of the gear
selector indicator. Near the top of this face plate the
following characters are imprinted from left to right:
ªP,º ªR,º ªN,º ªD,º ª2,º and ª1.º Respectively, these
characters represent the park, reverse, neutral,
drive, second gear, and first gear positions of the
transmission gear selector lever on the steering col-
umn. Directly below each character on the face plateis a small, rectangular window, and behind these
windows is a single, movable red pointer.
The gear selector indicator graphics are white
against a black field except for the single red pointer,
making them clearly visible within the instrument
cluster in daylight. When illuminated from behind by
the panel lamps dimmer controlled cluster illumina-
tion lighting with the exterior lamps turned On, the
white graphics appear blue-green, while the red
pointer still appears red. Indicator illumination is
provided by replaceable incandescent bulb and bulb
holder units located on the instrument cluster elec-
tronic circuit board. The gear selector indicator is
available for service replacement separate from the
instrument cluster. The instrument cluster must be
removed from the instrument panel for service access
to the gear selector indicator. (Refer to 8 - ELECTRI-
CAL/INSTRUMENT CLUSTER - REMOVAL).
OPERATION
The mechanical gear selector indicator gives an
indication of the transmission gear that has been
selected with the automatic transmission gear selec-
tor lever. A red pointer appears in a window below
the character in the indicator representing the trans-
mission gear that has been selected. The small,
spring-loaded pointer moves on a track through a
trolley-like mechanism within the indicator housing.
A short length of small diameter stranded cable is
attached to one side of the pointer trolley and is
encased in a tubular plastic housing that exits the
right side of the indicator. The cable is routed
through the instrument panel and under the steering
column to the left side of the column. The looped end
of the cable is hooked over the end of the PRNDL
driver lever on the steering column gearshift mecha-
nism, and the cable housing is secured in a molded
plastic adjuster and bracket on the column housing.
When the gear selector lever is moved the PRNDL
driver lever moves, which moves the pointer through
the mechanical actuator cable. The cable adjuster
and bracket unit mounted on the steering column
housing provides a mechanical means of calibrating
the gear selector indicator mechanism. (Refer to 19 -
STEERING/COLUMN - INSTALLATION).
HIGH BEAM INDICATOR
DESCRIPTION
A high beam indicator is standard equipment on
all instrument clusters. The high beam indicator is
located near the upper edge of the instrument cluster
overlay, between the tachometer and the speedome-
ter. The high beam indicator consists of a stenciled
cutout of the International Control and Display Sym-
BR/BEINSTRUMENT CLUSTER 8J - 21
FUEL GAUGE (Continued)

OVERDRIVE OFF INDICATOR
DESCRIPTION
An overdrive off indicator is standard equipment
on all instrument clusters. However, on vehicles not
equipped with the optional overdrive automatic
transmission, this indicator is electronically disabled.
The overdrive off indicator is located near the lower
edge of the instrument cluster overlay, to the right of
center. The overdrive off indicator consists of a sten-
cilled cutout of the words ªO/D OFFº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. An
amber lens behind the cutout in the opaque layer of
the overlay causes the ªO/D OFFº text to appear in
amber through the translucent outer layer of the
overlay when the indicator is illuminated from
behind by a Light Emitting Diode (LED) soldered
onto the instrument cluster electronic circuit board.
The overdrive off indicator is serviced as a unit with
the instrument cluster.
OPERATION
The overdrive off indicator gives an indication to
the vehicle operator when the Off position of the
overdrive off switch has been selected, disabling the
electronically controlled overdrive feature of the auto-
matic transmission. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon the cluster programming and electronic
messages received by the cluster from the Powertrain
Control Module (PCM) over the Chrysler Collision
Detection (CCD) data bus. The overdrive off indicator
Light Emitting Diode (LED) receives battery current
on the instrument cluster electronic circuit board
through the fused ignition switch output (st-run) cir-
cuit whenever the ignition switch is in the On or
Start positions; therefore, the LED will always be off
when the ignition switch is in any position except On
or Start. The LED only illuminates when it is pro-
vided a path to ground by the instrument cluster
transistor. The instrument cluster will turn on the
overdrive off indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the overdrive off indicator
is illuminated for about two seconds as a bulb test.
²Overdrive Off Lamp-On Message- Each time
the cluster receives an overdrive off lamp-on message
from the PCM indicating that the Off position of the
overdrive off switch has been selected, the overdrive
off indicator will be illuminated. The indicator
remains illuminated until the cluster receives an
overdrive off lamp-off message from the PCM, or
until the ignition switch is turned to the Off position,
whichever occurs first.²Actuator Test- Each time the cluster is put
through the actuator test, the indicator will be
turned on during the bulb check portion of the test to
confirm the functionality of the LED and the cluster
control circuitry.
The PCM continually monitors the overdrive off
switch to determine the proper outputs to the auto-
matic transmission, then sends the proper messages
to the instrument cluster. For further diagnosis of
the overdrive off indicator or the instrument cluster
circuitry that controls the LED, (Refer to 8 - ELEC-
TRICAL/INSTRUMENT CLUSTER - DIAGNOSIS
AND TESTING). For proper diagnosis of the over-
drive control system, the PCM, the CCD data bus, or
the message inputs to the instrument cluster that
control the overdrive off indicator, a DRBIIItscan
tool is required. Refer to the appropriate diagnostic
information.
SEATBELT INDICATOR
DESCRIPTION
A seatbelt indicator is standard equipment on all
instrument clusters. The seatbelt indicator is located
near the lower edge of the instrument cluster overlay,
to the right of center. The seatbelt indicator consists
of a stencilled cutout of the International Control and
Display Symbol icon for ªSeat Beltº in the opaque
layer of the instrument cluster overlay. The dark
outer layer of the overlay prevents the indicator from
being clearly visible when it is not illuminated. A red
lens behind the cutout in the opaque layer of the
overlay causes the icon to appear in red through the
translucent outer layer of the overlay when the indi-
cator is illuminated from behind by a Light Emitting
Diode (LED) soldered onto the instrument cluster
electronic circuit board. The seatbelt indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The seatbelt indicator gives an indication to the
vehicle operator of the status of the driver side front
seatbelt buckle. This indicator is controlled by a tran-
sistor on the instrument cluster circuit board based
upon the cluster programming, and a hard wired
input from the seatbelt switch in the driver side front
seatbelt through the seat belt switch sense circuit.
The seatbelt indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, the
lamp will always be off when the ignition switch is in
any position except On or Start. The LED only illu-
minates when it is switched to ground by the instru-
ment cluster transistor. The instrument cluster will
BR/BEINSTRUMENT CLUSTER 8J - 27

OPERATION
The ambient photocell sensor is located on the for-
ward-facing (windshield side) of the rear view mirror
housing, and detects the ambient light levels outside
of the vehicle. The headlamp photocell sensor is
located inside the rear view mirror housing behind
the mirror glass and faces rearward, to detect the
level of the light being received at the rear window
side of the mirror. When the circuitry of the auto-
matic day/night mirror detects that the difference
between the two light levels is too great (the light
level received at the rear of the mirror is much
higher than that at the front of the mirror), it begins
to darken the mirror.
The automatic day/night mirror circuitry also mon-
itors the transmission using an input from the
backup lamp circuit. The mirror circuitry is pro-
grammed to automatically disable its self-dimming
feature whenever it senses that the transmission
backup lamp circuit is energized.
The automatic day/night mirror is a completely
self-contained unit and cannot be repaired. If faulty
or damaged, the entire mirror assembly must be
replaced.
DIAGNOSIS AND TESTING - AUTOMATIC
DAY/NIGHT MIRROR
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
(1) Check the fuse in the junction block. If OK, go
to Step 2. If not OK, repair the shorted circuit or
component as required replace the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the junction
block. If OK, go to Step 3. If not OK, repair the open
circuit to the ignition switch as required.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Unplug the wire harness connector from the auto-
matic day/night mirror (Fig. 1). Connect the battery
negative cable. Turn the ignition switch to the On
position. Check for battery voltage at the fused igni-
tion switch output (run/start) circuit cavity of the
automatic day/night mirror wire harness connector. If
OK, go to Step 4. If not OK, repair the open circuit to
the junction block as required.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Check for continuity between the ground circuit cav-
ity of the automatic day/night mirror wire harness
connector and a good ground. There should be conti-nuity. If OK, go to Step 5. If not OK, repair the cir-
cuit to ground as required.
(5) Connect the battery negative cable. Turn the
ignition switch to the On position. Set the parking
brake. Place the transmission gear selector lever in
the Reverse position. Check for battery voltage at the
backup lamp switch output circuit cavity of the auto-
matic day/night mirror wire harness connector. If
OK, go to Step 6. If not OK, repair the open circuit
as required.
(6) Turn the ignition switch to the Off position.
Disconnect the battery negative cable. Plug in the
automatic day/night mirror wire harness connector.
Connect the battery negative cable. Turn the ignition
switch to the On position. Place the transmission
gear selector lever in the Neutral position. Place the
mirror switch in the On (LED in the mirror switch is
lighted) position. Cover the forward facing ambient
photocell sensor to keep out any ambient light.
NOTE: The ambient photocell sensor must be cov-
ered completely, so that no light reaches the sen-
sor. Use a finger pressed tightly against the sensor,
or cover the sensor completely with electrical tape.
(7) Shine a light into the rearward facing head-
lamp photocell sensor. The mirror glass should
darken. If OK, go to Step 8. If not OK, replace the
faulty automatic day/night mirror unit.
(8) With the mirror glass darkened, place the
transmission gear selector lever in the Reverse posi-
tion. The mirror should return to its normal reflec-
tance. If not OK, replace the faulty automatic day/
night mirror unit.
Fig. 1 Automatic Day/Night Mirror
BR/BEPOWER MIRRORS 8N - 11
AUTOMATIC DAY / NIGHT MIRROR (Continued)

(9) Turn the ignition switch to the Off position for
about fifteen seconds, and then back to the On posi-
tion. Observe the airbag indicator in the instrument
cluster. It should light for six to eight seconds, and
then go out. This indicates that the airbag system is
functioning normally and that the repairs are com-
plete. If the airbag indicator fails to light, or lights
and stays on, there is still an active airbag system
fault or malfunction. Refer to the appropriate diag-
nostic information to diagnose the problem.
SPECIAL TOOLS
SPECIAL TOOLS - AIRBAG SYSTEM
AIRBAG CONTROL MODULE
DESCRIPTION
The Airbag Control Module (ACM) is concealed
underneath the plastic ACM trim cover (automatic
transmission) or center console (manual transmis-
sion), directly below the instrument panel in the pas-
senger compartment of the vehicle. The ACM is
secured with screws to a mounting bracket located
under the instrument panel center support bracket
on the floor panel transmission tunnel. The ACM
contains an electronic microprocessor, an electronic
impact sensor, an electromechanical safing sensor,
and an energy storage capacitor. The ACM is con-
nected to the vehicle electrical system through a take
out and connector of the instrument panel wire har-
ness.
The ACM cannot be repaired or adjusted and, if
damaged or faulty, it must be replaced.
OPERATION
The microprocessor in the ACM contains the airbag
system logic circuits, and it monitors and controls all
of the airbag system components. The ACM also uses
On-Board Diagnostics (OBD) and can communicate
with other electronic modules in the vehicle as well
as with the DRBIIItscan tool using the Chrysler
Collision Detection (CCD) data bus network. This
method of communication is used for control of the
airbag indicator in the ElectroMechanical InstrumentCluster (EMIC) and for airbag system diagnosis and
testing through the 16-way data link connector
located on the lower left edge of the instrument
panel. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/COMMUNICATION - OPER-
ATION). The ACM microprocessor continuously mon-
itors all of the airbag system electrical circuits to
determine the system readiness. If the ACM detects
a monitored system fault, it sets an active Diagnostic
Trouble Code (DTC) and sends messages to the
EMIC over the CCD data bus to turn on the airbag
indicator. (Refer to 8 - ELECTRICAL/INSTRUMENT
CLUSTER/AIRBAG INDICATOR - OPERATION). If
the airbag system fault is still present when the igni-
tion switch is turned to the Off position, the DTC is
stored in memory by the ACM. However, if a fault
does not recur for a number of ignition cycles, the
ACM will automatically erase the stored DTC.
The ACM receives battery current through two cir-
cuits, on a fused ignition switch output (run) circuit
through a fuse in the Junction Block (JB), and on a
fused ignition switch output (start-run) circuit
through a second fuse in the JB. The ACM is
grounded through a ground circuit and take out of
the instrument panel wire harness. This take out has
a single eyelet terminal connector secured by a nut to
a ground stud located on the forward extension of the
left front fender wheel housing in the engine com-
partment. Therefore, the ACM is operational when-
ever the ignition switch is in the Start or On
positions. The ACM also contains an energy-storage
capacitor. When the ignition switch is in the Start or
On positions, this capacitor is continually being
charged with enough electrical energy to deploy the
airbags for up to one second following a battery dis-
connect or failure. The purpose of the capacitor is to
provide backup airbag system protection in case
there is a loss of battery current supply to the ACM
during an impact. The capacitor is only serviced as a
unit with the ACM.
Two sensors are contained within the ACM, an
electronic impact sensor and a safing sensor. The
electronic impact sensor is an accelerometer that
senses the rate of vehicle deceleration, which pro-
vides verification of the direction and severity of an
impact. A pre-programmed decision algorithm in the
ACM microprocessor determines when the decelera-
tion rate as signaled by the impact sensor indicates
an impact that is severe enough to require airbag
system protection. When the programmed conditions
are met, the ACM sends an electrical signal to deploy
the airbags. The safing sensor is an electromechani-
cal sensor within the ACM that is connected in series
between the ACM microprocessor airbag deployment
circuit and the airbags. The safing sensor is a nor-
mally open switch that is used to verify or confirm
Puller C-3428-B
8O - 6 RESTRAINTSBR/BE
RESTRAINTS (Continued)

the need for an airbag deployment by detecting
impact energy of a lesser magnitude than that of the
electronic impact sensor, and must be closed in order
for the airbags to deploy. The impact sensor and saf-
ing sensor are calibrated for the specific vehicle, and
are only serviced as a unit with the ACM.
REMOVAL
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
WARNING: THE AIRBAG CONTROL MODULE CON-
TAINS THE IMPACT SENSOR, WHICH ENABLES
THE SYSTEM TO DEPLOY THE AIRBAGS. NEVER
STRIKE OR KICK THE AIRBAG CONTROL MODULE,
AS IT CAN DAMAGE THE IMPACT SENSOR OR
AFFECT ITS CALIBRATION. IF AN AIRBAG CON-
TROL MODULE IS ACCIDENTALLY DROPPED DUR-
ING SERVICE, THE MODULE MUST BE SCRAPPED
AND REPLACED WITH A NEW UNIT. FAILURE TO
OBSERVE THIS WARNING COULD RESULT IN ACCI-
DENTAL, INCOMPLETE, OR IMPROPER AIRBAG
DEPLOYMENT AND POSSIBLE OCCUPANT INJU-
RIES.
(1) Disconnect and isolate the battery negative
cable. If either of the airbags has not been deployed,
wait two minutes for the system capacitor to dis-
charge before further service.
(2) If the vehicle is equipped with a manual trans-
mission, remove the center floor console from the
floor panel transmission tunnel. (Refer to 23 - BODY/
INTERIOR/CENTER CONSOLE - REMOVAL).
(3) If the vehicle is equipped with an automatic
transmission, remove the two screws that secure the
trim cover to the Airbag Control Module (ACM)
mounting bracket on the floor panel transmission
tunnel and remove the trim cover (Fig. 5).
(4) Loosen the screw that secures each side of the
instrument panel center support bracket to the ACM
mounting bracket (Fig. 6). Do not remove these
screws.
(5) Remove the two nuts that secure the instru-
ment panel center support bracket to the studs on
the lower instrument panel structural support.
Fig. 5 Airbag Control Module Trim Cover Remove/
Install
1 - INSTRUMENT PANEL CENTER SUPPORT BRACKET
2 - ACM MOUNTING BRACKET
3 - TRIM COVER
4 - SCREW (2)
Fig. 6 Airbag Control Module Remove/Install
1 - INSTRUMENT PANEL
2 - CENTER SUPPORT BRACKET
3 - SCREW (2)
4 - FLOOR PANEL
5 - SCREW (4)
6 - ACM MOUNTING BRACKET
7 - CONNECTOR
8 - AIRBAG CONTROL MODULE
9 - RETAINER
10 - NUT (2)
BR/BERESTRAINTS 8O - 7
AIRBAG CONTROL MODULE (Continued)

(6) Disengage the retainer on the instrument
panel wire harness take out to the ACM from the
retainer hole in the left side of the instrument panel
center support bracket.
(7) Pull the top of the instrument panel center
support bracket rearward and down from the instru-
ment panel studs. Fold it down over the top of the
ACM until it is laying flat on the floor panel trans-
mission tunnel.
(8) Disconnect the instrument panel wire harness
connector for the ACM from the ACM connector
receptacle. To disconnect this connector:
(a) Slide the red Connector Position Assurance
(CPA) lock on the top of the connector toward the
side of the vehicle.
(b) Depress the connector latch tab and pull the
connector straight away from the ACM connector
receptacle.
NOTE: Always remove and replace the ACM and its
mounting bracket as a unit. Replacement modules
include a replacement mounting bracket. Do not
transfer the ACM to another mounting bracket.
(9) Remove the four screws that secure the ACM
mounting bracket to the floor panel transmission
tunnel.
(10) Remove the ACM, the mounting bracket, and
the instrument panel center support bracket from the
floor panel transmission tunnel as a unit.
INSTALLATION
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
WARNING: THE AIRBAG CONTROL MODULE CON-
TAINS THE IMPACT SENSOR, WHICH ENABLES
THE SYSTEM TO DEPLOY THE AIRBAGS. NEVER
STRIKE OR KICK THE AIRBAG CONTROL MODULE,
AS IT CAN DAMAGE THE IMPACT SENSOR OR
AFFECT ITS CALIBRATION. IF AN AIRBAG CON-
TROL MODULE IS ACCIDENTALLY DROPPED DUR-
ING SERVICE, THE MODULE MUST BE SCRAPPED
AND REPLACED WITH A NEW UNIT. FAILURE TOOBSERVE THIS WARNING COULD RESULT IN ACCI-
DENTAL, INCOMPLETE, OR IMPROPER AIRBAG
DEPLOYMENT AND POSSIBLE OCCUPANT INJU-
RIES.
(1) Carefully position the Airbag Control Module
(ACM), the mounting bracket, and the instrument
panel center support bracket onto the floor panel
transmission tunnel as a unit (Fig. 6). When the
ACM is correctly positioned, the arrow on the ACM
label will be pointed forward in the vehicle.
(2) Install and tighten the four screws that secure
the ACM mounting bracket to the floor panel trans-
mission tunnel. Tighten the screws to 14 N´m (125
in. lbs.).
(3) With the instrument panel center support
bracket still folded down flat on the floor panel trans-
mission tunnel, reconnect the instrument panel wire
harness connector for the ACM to the ACM connector
receptacle. Be certain that the connector latch and
the red Connector Position Assurance (CPA) lock are
fully engaged.
(4) Fold the top of the instrument panel center
support bracket up over the top of the ACM and for-
ward over the studs on the lower instrument panel
structural support.
(5) Install and tighten the nuts that secure the
instrument panel center support bracket to the studs
on the lower instrument panel structural support.
Tighten the nuts to 14 N´m (125 in. lbs.).
(6) Engage the retainer on the instrument panel
wire harness take out for the ACM in the retainer
hole on the left side of the instrument panel center
support bracket.
(7) Tighten the screws that secure each side of the
instrument panel center support bracket to the ACM
mounting bracket. Tighten the screws 14 N´m (125
in. lbs.).
(8) If the vehicle is equipped with an automatic
transmission, position the ACM trim cover to the
ACM mounting bracket on the floor panel transmis-
sion tunnel (Fig. 5).
(9) If the vehicle is equipped with an automatic
transmission, install and tighten the two screws that
secure the ACM trim cover to the ACM mounting
bracket. Tighten the screws to 2.2 N´m (20 in. lbs.).
(10) If the vehicle is equipped with a manual
transmission, reinstall the center floor console onto
the floor panel transmission tunnel. (Refer to 23 -
BODY/INTERIOR/CENTER CONSOLE - INSTALLA-
TION).
(11) Do not reconnect the battery negative cable at
this time. The airbag system verification test proce-
dure should be performed following service of any
airbag system component. (Refer to 8 - ELECTRI-
CAL/RESTRAINTS - STANDARD PROCEDURE -
VERIFICATION TEST).
8O - 8 RESTRAINTSBR/BE
AIRBAG CONTROL MODULE (Continued)

SPEED CONTROL
TABLE OF CONTENTS
page page
SPEED CONTROL
DESCRIPTION............................1
OPERATION.............................2
DIAGNOSIS AND TESTING..................2
VACUUM SUPPLY.......................2
ROAD TEST............................3
SPECIFICATIONS.........................4
CABLE
DESCRIPTION............................4
OPERATION.............................4
REMOVAL...............................4
INSTALLATION............................4
SPEED CONTROL SERVO
DESCRIPTION............................5OPERATION.............................5
REMOVAL...............................6
INSTALLATION...........................10
SWITCH
DESCRIPTION...........................12
OPERATION.............................12
REMOVAL..............................13
INSTALLATION...........................13
VACUUM RESERVOIR
DESCRIPTION...........................13
REMOVAL..............................13
INSTALLATION...........................14
SPEED CONTROL
DESCRIPTION - SPEED CONTROL SYSTEM
Gas Engines and/or Diesel With Automatic Trans.
The speed control system is operated by the use of
a cable and a vacuum controlled servo. Electronic
control of the speed control system is integrated into
the Powertrain Control Module (PCM). The controls
consist of two steering wheel mounted switches. The
switches are labeled: ON/OFF, RES/ACCEL, SET,
COAST, and CANCEL.
The system is designed to operate at speeds above
30 mph (50 km/h).
WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
Diesel With Manual Trans.
The speed control system is fully electronically con-
trolled by the Engine Control Module (ECM).A
cable and a vacuum controlled servo are not
used if the vehicle is equipped with a manual
transmission and a diesel engine. This is a ser-
vo-less system.The controls consist of two steering
wheel mounted switches. The switches are labeled:
ON/OFF, RES/ACCEL, SET, COAST, and CANCEL.
The system is designed to operate at speeds above
30 mph (50 km/h).WARNING: THE USE OF SPEED CONTROL IS NOT
RECOMMENDED WHEN DRIVING CONDITIONS DO
NOT PERMIT MAINTAINING A CONSTANT SPEED,
SUCH AS IN HEAVY TRAFFIC OR ON ROADS THAT
ARE WINDING, ICY, SNOW COVERED, OR SLIP-
PERY.
DESCRIPTION - VEHICLE SPEED INPUT
Gas Engines and/or Diesel With Automatic Trans.
The Vehicle Speed Sensor (VSS) is no longer used
for any Dodge Truck.
Vehicle speed and distance covered are measured by
the Rear Wheel Speed Sensor. The sensor is mounted
to the rear axle. A signal is sent from this sensor to the
Controller Antilock Brake (CAB) computer. A signal is
then sent from the CAB to the Powertrain Control
Module (PCM) to determine vehicle speed and distance
covered. The PCM will then determine strategies for
speed control system operation.
Diesel With Manual Trans.
The Vehicle Speed Sensor (VSS) is no longer used
for any Dodge Truck.
Vehicle speed and distance covered are measured
by the Rear Wheel Speed Sensor. The sensor is
mounted to the rear axle. A signal is sent from this
sensor to the Controller Antilock Brake (CAB) com-
puter. A signal is then sent from the CAB to the
Engine Control Module (ECM) to determine vehicle
speed and distance covered. The ECM will then
determine strategies for speed control system opera-
tion.
BR/BESPEED CONTROL 8P - 1

OPERATION - SPEED CONTROL SYSTEM
Gas Engines and/or Diesel With Automatic Trans.
When speed control is selected by depressing the
ON switch, the PCM allows a set speed to be stored
in PCM RAM for speed control. To store a set speed,
depress the SET switch while the vehicle is moving
at a speed between 35 and 85 mph. In order for the
speed control to engage, the brakes cannot be
applied, nor can the gear selector be indicating the
transmission is in Park or Neutral.The speed control
can be disengaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
²Depressing the clutch pedal (if equipped)
NOTE: Depressing the OFF switch or turning off the
ignition switch will erase the set speed stored in
the PCM.
For added safety, the speed control system is pro-
grammed to disengage for any of the following condi-
tions:
²An indication of Park or Neutral
²A rapid increase of rpm (indication that the
clutch has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The speed signal increases at a rate of 10 mph
per second (indicates that the coefficient of friction
between the road surface and tires is extremely low)
²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)
Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the PCM.
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
PCM when the RES/ACCEL is released. The PCM
also has a9tap-up9feature in which vehicle speed
increases at a rate of approximately 2 mph for each
momentary switch activation of the RES/ACCEL
switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.
Diesel With Manual Trans.
When speed control is selected by depressing the
ON switch, the Engine Control Module (ECM) allows
a set speed to be stored in ECM RAM for speed con-trol. To store a set speed, depress the SET switch
while the vehicle is moving at a speed between 35
and 85 mph. In order for the speed control to engage,
the brakes cannot be applied.The speed control can
be disengaged manually by:
²Stepping on the brake pedal
²Depressing the OFF switch
²Depressing the CANCEL switch.
²Depressing the clutch pedal
NOTE: Depressing the OFF switch or turning off the
ignition switch will erase the set speed stored in
the ECM.
For added safety, the speed control system is pro-
grammed to disengage for any of the following condi-
tions:
²A rapid increase of rpm (indication that the
clutch has been disengaged)
²Excessive engine rpm (indicates that the trans-
mission may be in a low gear)
²The speed signal increases at a rate of 10 mph
per second (indicates that the coefficient of friction
between the road surface and tires is extremely low)
²The speed signal decreases at a rate of 10 mph
per second (indicates that the vehicle may have
decelerated at an extremely high rate)
Once the speed control has been disengaged,
depressing the RES/ACCEL switch (when speed is
greater than 30 mph) restores the vehicle to the tar-
get speed that was stored in the ECM.
While the speed control is engaged, the driver can
increase the vehicle speed by depressing the RES/AC-
CEL switch. The new target speed is stored in the
ECM when the RES/ACCEL is released. The ECM also
has a9tap-up9feature in which vehicle speed increases
at a rate of approximately 2 mph for each momentary
switch activation of the RES/ACCEL switch.
A ªtap downº feature is used to decelerate without
disengaging the speed control system. To decelerate
from an existing recorded target speed, momentarily
depress the COAST switch. For each switch activa-
tion, speed will be lowered approximately 1 mph.
DIAGNOSIS AND TESTING - VACUUM SUPPLY
Gas Powered Engines
On gasoline powered engines: actual engine vac-
uum, a vacuum reservoir, a one-way check valve and
vacuum lines are used to supply vacuum to the speed
control servo.
(1)
Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected hose.
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury.
8P - 2 SPEED CONTROLBR/BE
SPEED CONTROL (Continued)