Power control DODGE RAM 1500 1998 2.G Workshop Manual

DRIVER SEAT SWITCH
DESCRIPTION
The power seat on this model can be adjusted in
eight different directions, up, down, front up, front
down, rear up, rear down, rearward and forward.
The power seat switch (Fig. 1) on this model has an
additional switch knob for adjusting the power lum-
bar support. The power seat switch is located on the
outboard side of the seat cushion on the seat cushion
side shield. Refer to the owner's manual in the vehi-
cle glove box for more information on the power seat
switch functions and the seat adjusting procedures.
The individual switches in the power seat switch
assembly cannot be repaired. If one switch is dam-
aged or faulty, the entire power seat switch assembly
must be replaced.
OPERATION
When a power switch control knob or knobs are
actuated, a battery feed and a ground path are
applied through the switch contacts to the power seat
track or recliner adjuster motor. The selected
adjuster motor operates to move the seat track or
recliner through its drive unit in the selected direc-
tion until the switch is released, or until the travel
limit of the adjuster is reached. When the switch ismoved in the opposite direction, the battery feed and
ground path to the motor are reversed through the
switch contacts. This causes the adjuster motor to
run in the opposite direction.
No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged.
DIAGNOSIS AND TESTING - DRIVER SEAT
SWITCH
For circuit descriptions and diagrams, refer to Wir-
ing.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the power seat switch from the power
seat.
(3) Use an ohmmeter to test the continuity of the
power seat switches in each position. See the Power
Seat Switch Continuity chart (Fig. 2). If OK, refer to
Power Seat Track Diagnosis and Testing in this
group. If not OK, replace the faulty power seat
switch.
DRIVER POWER SEAT SWITCH TEST TABLE
DRIVER SWITCH
POSITIONCONTINUITY BETWEEN
OFF B-N, B-J, B-M
B-E, B-L, B-K
VERTICAL UP A-E, A-M, B-N, B-J
VERTICAL DOWN A-J, A-N, B-M, B-E
Fig. 1 DR Power Seat Switch
1 - POWER SEAT SWITCH ASSEMBLY
2 - FRONT SEAT CUSHION ADJUSTMENT BUTTON
3 - COMPLETE SEAT ADJUSTMENT BUTTON
4 - REAR SEAT CUSHION ADJUSTMENT BUTTON
5 - LUMBAR ADJUSTMENT BUTTON
Fig. 2 Testing Driver Power Seat Switch
8N - 14 POWER SEATSDR

DRIVER POWER SEAT SWITCH TEST TABLE
DRIVER SWITCH
POSITIONCONTINUITY BETWEEN
HORIZONTAL
FORWARDA-L, B-K
HORIZONTAL
REARWARDA-K, B-L
FRONT TILT UP A-M, B-N
FRONT TILT DOWN A-N, B-M
REAR TILT UP A-E, B-J
REAR TILT DOWN A-J, B-E
LUMBAR OFF O-P, O-R, P-R
LUMPAR UP (INFLATE) O-P, Q-R
LUMBAR DOWN
(DEFLATE)O-R, P-Q
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the seat cushion side shield from the
seat. Refer to the Body section of the service manual
for the procedure.
(3) Pull the switch bezel or side shield unit out
from the seat far enough to access the switch wire
harness connector. Gently pry the locking tabs of the
switch away from the wire harness connector and
carefully unplug the connector from the power seat
switch module.
(4) Remove the screws that secure the power seat
switch.
INSTALLATION
(1) Position the power seat switch on the seat
cushion side shield and install the screws that secure
the power seat switch to seat cushion side shield.
(2) Connect the electrical connector.
(3) Install the seat cushion side shield on the seat.
Refer to the Body section of the service manual for
the procedure.
(4) If equipped, install the screw that secures the
recliner lever to the recliner mechanism release shaft
on the outboard side of the front seat.
(5) Connect the battery negative cable.
PASSENGER SEAT SWITCH
DESCRIPTION
The power seat on this model can be adjusted in
eight different directions, up, down, front up, front
down, rear up, rear down, rearward and forward.
The power seat switch (Fig. 3) on this model has an
additional switch knob for adjusting the power lum-bar support. The power seat switch is located on the
outboard side of the seat cushion on the seat cushion
side shield. Refer to the owner's manual in the vehi-
cle glove box for more information on the power seat
switch functions and the seat adjusting procedures.
The individual switches in the power seat switch
assembly cannot be repaired. If one switch is dam-
aged or faulty, the entire power seat switch assembly
must be replaced.
OPERATION
When a power switch control knob or knobs are
actuated, a battery feed and a ground path are
applied through the switch contacts to the power seat
track or recliner adjuster motor. The selected
adjuster motor operates to move the seat track or
recliner through its drive unit in the selected direc-
tion until the switch is released, or until the travel
limit of the adjuster is reached. When the switch is
moved in the opposite direction, the battery feed and
ground path to the motor are reversed through the
switch contacts. This causes the adjuster motor to
run in the opposite direction.
No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged.
Fig. 3 DR Power Seat Switch
1 - POWER SEAT SWITCH ASSEMBLY
2 - FRONT SEAT CUSHION ADJUSTMENT BUTTON
3 - COMPLETE SEAT ADJUSTMENT BUTTON
4 - REAR SEAT CUSHION ADJUSTMENT BUTTON
5 - LUMBAR ADJUSTMENT BUTTON
DRPOWER SEATS 8N - 15
DRIVER SEAT SWITCH (Continued)

they can be operated in unison by selecting the
proper power seat switch functions, which will raise
or lower the entire seat assembly. The third motor is
the horizontal adjustment motor, which moves the
seat track in the forward and rearward directions.
DIAGNOSIS AND TESTING - POWER SEAT
TRACK
For complete power seat circuit descriptions and
diagrams, refer to Wiring Diagrams.
Operate the power seat switch to move all three
seat motors in each direction. The seat should move
in each of the selected directions. If the power seat
track fails to operate in only one direction, move the
seat track a short distance in the opposite direction
and test again to be certain that the track is not at
its travel limit. If the power seat track still fails to
operate in only one direction, refer to Diagnosis and
Testing of the Power Seat Switch in this section. If
the power seat track fails to operate in more than
one direction, proceed as follows:
(1) Check the power seat fuse in the power distri-
bution center. If OK, go to Step 2. If not OK, replace
the faulty fuse.
(2) Remove the power seat switch from the seat.
Check for battery voltage at the fused B(+) circuit
cavity of the power seat switch wire harness connec-
tor. If OK, go to Step 3. If not OK, repair the open
circuit to the power distribution center as required.(3) Check for continuity between the ground cir-
cuit cavity of the power seat switch wire harness con-
nector and a good ground. There should be
continuity. If OK, go to Step 4. If not OK, repair the
open circuit to ground as required.
(4) Test the power seat switch as described in this
group. If the switch tests OK, check the wire harness
between the power seat switch and the motor for
shorts or opens. If the circuits check OK, replace the
faulty power seat track (adjuster) assembly. If the
circuits are not OK, repair the wire harness as
required.
REMOVAL
(1) Remove the appropriate seat from the vehicle.
(Refer to 23 - BODY/SEATS/SEAT - REMOVAL).
(2) Remove the power seat switch from the seat.
Refer to the procedure in this section of the service
manual.
(3) Remove four seat track mounting nuts from
cushion pan.
(4) Disconnect the power seat electrical and
remove the seat track from the seat cushion.
(5) Remove the necessary components that must
be transferred to the replacement seat track (seat
belt buckles, wire harness, etc.).
INSTALLATION
(1) Install the necessary components that must be
transferred to the replacement seat track (seat belt
buckles, wire harness, etc.).
(2) Position the seat track and install the retaining
nuts on the seat cushion pan studs. Torque the bolts
to 25 N´m.
(3) Route and connect the power seat electrical on
the seat track and cushion pan.
(4) Install the power seat switch on the seat. Refer
to the procedure in this section of the service man-
ual.
(5) Install the seat in the vehicle (Refer to 23 -
BODY/SEATS/SEAT - INSTALLATION).
(6) Connect the negative battery cable.
LUMBAR CONTROL SWITCH
DESCRIPTION
The power lumbar seat option includes an electri-
cally operated lumbar support mechanism. A single
two-way momentary power lumbar switch is integral
with the power seat switches. The power lumbar
switch is secured to the back of the seat cushion side
shield with screws, and the switch paddle protrudes
through a hole to the outside of the shield. The
switch paddle is located in a shallow depression
molded into the outer surface of the seat cushion side
Fig. 5 DR Driver Power Seat Track
1 - POWER SEAT TRACK ASSEMBLY
2 - SEAT TRACK WIRE HARNESS
3 - SEAT BELT BUCKLE ASSEMBLIES
DRPOWER SEATS 8N - 17
POWER SEAT TRACK (Continued)

shield that helps to shroud it from unintentional
actuation when entering or leaving the vehicle.
The power lumbar switches cannot be adjusted or
repaired and, if faulty or damaged, the seat switch
assembly must be replaced.
OPERATION
When the power lumbar switch paddle is actuated,
a battery feed and a ground path are applied through
the switch contacts to the power lumbar adjuster
motor. The motor operates to move the lumbar
adjuster through its drive unit in the selected direc-
tion until the switch is released, or until the travel
limit of the adjuster is reached. When the switch is
moved in the opposite direction, the battery feed and
ground path to the motor are reversed through the
switch contacts. This causes the motor to run in the
opposite direction.
The power lumbar switch should not be held
applied in either direction after the adjuster has
reached its travel limit. The power lumbar adjuster
motor contains a self-resetting circuit breaker to pro-
tect it from overload. However, consecutive or fre-
quent resetting of the circuit breaker must not be
allowed to continue, or the motor may be damaged.
REMOVAL
The power lumbar switch is integral with the other
power seat switches. Refer to the appropriate driver
or passenger power front seat switch removal and/or
installation procedure.
LUMBAR MOTOR
DESCRIPTION
The power lumbar seat option includes an electri-
cally operated lumbar support mechanism. The only
visible evidence of this option is the separate power
lumbar switch control paddle that is located on the
outboard seat cushion switch bezel, next to the other
power seat switch control knobs. The power lumbar
adjuster and motor are concealed beneath the seat
back trim cover and padding, where they are secured
to a molded plastic back panel and to the seat back
frame.
The power lumbar adjuster cannot be repaired, and
is serviced only as a unit with the seat back frame. If
the power lumbar adjuster or the seat back frame
are damaged or faulty, the entire seat back frame
unit must be replaced (Refer to 23 - BODY/SEATS/
SEAT BACK - REMOVAL).
OPERATION
The power lumbar adjuster mechanism includes a
reversible electric motor that is secured to theinboard side of the seat back panel and is connected
to a worm-drive gearbox. The motor and gearbox
operate the lumbar adjuster mechanism in the center
of the seat back driving a nut up or down a fixed
drive screw. The action of this nut extends or con-
tracts the plastic lumbar support band. The more
this band is contracted, the more outward pressure is
applied against the center of the seat back padding,
providing additional lumbar support.
DIAGNOSIS AND TESTING - LUMBAR MOTOR
Actuate the power lumbar switch to move the
power lumbar adjuster in each direction. The power
lumbar adjuster should move in both directions. It
should be noted that the power lumber adjuster nor-
mally operates very quietly and exhibits little visible
movement. If the power lumbar adjuster fails to oper-
ate in only one direction, move the adjuster a short
distance in the opposite direction and test again to be
certain that the adjuster is not at its travel limit. If
the power lumbar adjuster fails to operate in only
one direction, Test the appropriate power seat switch
as described in this group. If the power lumbar
adjuster fails to operate in either direction, perform
the following tests. For complete circuit diagrams,
refer toWiring.
(1) Check the power seat circuit breaker. If OK, go
to Step 2. If not OK, replace the faulty power seat
circuit breaker.
(2) Check for battery voltage at the power seat cir-
cuit breaker. If OK, go to Step 3. If not OK, repair
the open fused B(+) circuit to the fuse in the Inte-
grated Power Module as required.
(3) Remove the outboard seat cushion side shield
from the seat. Disconnect the seat wire harness con-
nector from the power lumbar switch connector
receptacle. Check for battery voltage at the fused
B(+) circuit cavity of the power seat wire harness
connector for the power lumbar switch. If OK, go to
Step 4. If not OK, repair the open fused B(+) circuit
to the power seat as required.
(4) Check for continuity between the ground cir-
cuit cavity of the power seat wire harness connector
for the power lumbar switch and a good ground.
There should be continuity. If OK, go to Step 5. If not
OK, repair the open ground circuit to ground as
required.
(5) Test the power lumbar switch. . If the switch
tests OK, test the circuits of the power seat wire har-
ness between the power lumbar adjuster motor and
the power lumbar switch for shorts or opens. If the
circuits check OK, replace the faulty seat back frame
assembly. If the circuits are not OK, repair the power
seat wire harness as required.
8N - 18 POWER SEATSDR
LUMBAR CONTROL SWITCH (Continued)

POWER WINDOWS
TABLE OF CONTENTS
page page
POWER WINDOWS
DESCRIPTION.........................19
OPERATION...........................19
DIAGNOSIS AND TESTING - POWER
WINDOWS...........................19
WINDOW MOTOR
REMOVAL.............................20WINDOW SWITCH
DIAGNOSIS AND TESTING - WINDOW
SWITCH............................20
REMOVAL.............................20
INSTALLATION.........................21
POWER WINDOWS
DESCRIPTION
The power window system allows each of the door
windows to be raised and lowered electrically by
actuating a switch on each door panel. A master
switch on the drivers door allows the driver to raise
or lower each of the passenger door windows and to
lock out the individual switches on the passenger
doors from operation. The power window system
receives battery feed through a fuse in the Integrated
Power Module (IPM) and a circuit breaker located in
the instrument panel wiring harness near the park
brake pedal, only when the ignition switch is in the
RUN or ACCESSORY position.
OPERATION
WINDOW SWITCH
The power window switches control the battery
and ground feeds to the power window motors. The
passenger door power window switches receive their
battery and ground feeds through the circuitry of the
drivers window switch. When the power window lock-
out switch is in the Lock position, the battery feed
for the passenger door window switches is inter-
rupted.
WINDOW MOTOR
Window motors use permanent type magnets. The
B+ and ground applied at the motor terminal pins
will cause the motor to rotate in one direction.
Reversing current through the motor terminals will
cause the motor to rotate in the opposite direction.
DIAGNOSIS AND TESTING - POWER
WINDOWS
WIRING VOLTAGE TEST
The following wiring test determines whether or
not voltage is continuous through the body harness
to the front switch.
(1) Remove the Driver Door Module (Refer to 8 -
ELECTRICAL/POWER LOCKS/DOOR MODULE -
REMOVAL).
(2) Disconnect wire connector from back of power
window switch.
(3) Switch ignition to the ON position.
(4) Connect the clip end of a 12 volt test light to
Pin 14 of the window switch harness connector.
Touch the test light probe to Pin 10.
²If the test light illuminates, the wiring circuit
between the battery and switch is OK.
²If the lamp does not illuminate, first check the
fuse in the Integrated Power Module (IPM). Check
the circuit breaker located near the park brake
pedal. If fuse and circuit breaker are OK, then check
for a broken wire.
Refer to the appropriate wiring information.
POWER WINDOW MOTOR TEST
If the power window motor is receiving proper cur-
rent and ground and does not operate, proceed with
motor test.
(1) Remove front door trim panel as necessary to
gain access to power window motor wire connector
(Refer to 23 - BODY/DOOR - FRONT/TRIM PANEL -
REMOVAL).
(2) Disconnect power window motor wire connector
from door harness.
(3) Using two jumper wires, connect one to a bat-
tery (+) source and the other to a good ground (-).
(4) Connect the Negative (-) jumper probe to one of
the motor connector terminals.
DRPOWER WINDOWS 8N - 19

resistance of the input from the on/off switch. The
ACM will also set and/or store a DTC for faults it
detects in the passenger airbag on/off switch circuits,
and will turn on the airbag indicator in the EMIC if
a fault has been detected.
The ACM receives battery current through two cir-
cuits; a fused ignition switch output (run) circuit
through a fuse in the Integrated Power Module
(IPM), and a fused ignition switch output (run-start)
circuit through a second fuse in the IPM. The ACM
receives ground through a ground circuit and take
out of the instrument panel wire harness. This take
out has a single eyelet terminal connector that is
secured by a ground screw to the instrument panel
support structure. These connections allow the ACM
to be operational whenever the ignition switch is in
the Start or On positions.
The ACM also contains an energy-storage capaci-
tor. When the ignition switch is in the Start or On
positions, this capacitor is continually being charged
with enough electrical energy to deploy the supple-
mental restraint components for up to one second fol-
lowing a battery disconnect or failure. The purpose of
the capacitor is to provide backup supplemental
restraint system protection in case there is a loss of
battery current supply to the ACM during an impact.
Two sensors are contained within the ACM, an
electronic impact sensor and a safing sensor. The
electronic impact sensors are accelerometers that
sense the rate of vehicle deceleration, which provide
verification of the direction and severity of an
impact. On models equipped with optional side cur-
tain airbags, the ACM also monitors inputs from two
remote side impact sensors located within both the
left and right B-pillars to control deployment of the
side curtain airbag units.
The safing sensor is an electronic accelerometer
sensor within the ACM that provides an additional
logic input to the ACM microprocessor. The safing
sensor is used to verify the need for a supplemental
restraint deployment by detecting impact energy of a
lesser magnitude than that of the primary electronic
impact sensors, and must exceed a safing threshold
in order for the airbags to deploy. Vehicles equipped
with optional side curtain airbags feature a second
safing sensor within the ACM to provide confirma-
tion to the ACM microprocessor of side impact forces.
This second safing sensor is a bi-directional unit that
detects impact forces from either side of the vehicle.
Pre-programmed decision algorithms in the ACM
microprocessor determine when the deceleration rate
as signaled by the impact sensors and the safing sen-
sors indicate an impact that is severe enough to
require supplemental restraint system protection
and, based upon the severity of the monitored impact
and the status of the passenger airbag on/off switchinput, determines the level of front airbag deploy-
ment force required for each front seating position.
When the programmed conditions are met, the ACM
sends the proper electrical signals to deploy the dual
multistage front airbags at the programmed force
levels, the front seat belt tensioners and, if the vehi-
cle is so equipped, either side curtain airbag unit.
The hard wired inputs and outputs for the ACM
may be diagnosed and tested using conventional
diagnostic tools and procedures. However, conven-
tional diagnostic methods will not prove conclusive in
the diagnosis of the ACM, the PCI data bus network,
or the electronic message inputs to and outputs from
the ACM. The most reliable, efficient, and accurate
means to diagnose the ACM, the PCI data bus net-
work, and the electronic message inputs to and out-
puts from the ACM requires the use of a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-
mation.
REMOVAL
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, ON VEHICLES EQUIPPED WITH AIRBAGS,
DISABLE THE SUPPLEMENTAL RESTRAINT SYS-
TEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, AIRBAG, SEAT BELT
TENSIONER, IMPACT SENSOR, OR INSTRUMENT
PANEL COMPONENT DIAGNOSIS OR SERVICE.
DISCONNECT AND ISOLATE THE BATTERY NEGA-
TIVE (GROUND) CABLE, THEN WAIT TWO MINUTES
FOR THE SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE SUPPLEMENTAL RESTRAINT SYSTEM.
FAILURE TO TAKE THE PROPER PRECAUTIONS
COULD RESULT IN ACCIDENTAL AIRBAG DEPLOY-
MENT.
WARNING: TO AVOID PERSONAL INJURY OR
DEATH, NEVER STRIKE OR DROP THE AIRBAG
CONTROL MODULE, AS IT CAN DAMAGE THE
IMPACT SENSOR OR AFFECT ITS CALIBRATION.
THE AIRBAG CONTROL MODULE CONTAINS THE
IMPACT SENSOR, WHICH ENABLES THE SYSTEM
TO DEPLOY THE SUPPLEMENTAL RESTRAINTS. IF
AN AIRBAG CONTROL MODULE IS ACCIDENTALLY
DROPPED DURING SERVICE, THE MODULE MUST
BE SCRAPPED AND REPLACED WITH A NEW UNIT.
FAILURE TO OBSERVE THIS WARNING COULD
RESULT IN ACCIDENTAL, INCOMPLETE, OR
IMPROPER SUPPLEMENTAL RESTRAINT DEPLOY-
MENT.
8O - 12 RESTRAINTSDR
AIRBAG CONTROL MODULE (Continued)

SPEED CONTROL
TABLE OF CONTENTS
page page
SPEED CONTROL
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - VACUUM
SUPPLY TEST.........................2
DIAGNOSIS AND TESTING - ROAD TEST....3
SPECIFICATIONS
TORQUE - SPEED CONTROL.............3
CABLE
DESCRIPTION..........................4
OPERATION............................4
REMOVAL.............................4
INSTALLATION..........................5
SERVO
DESCRIPTION..........................6OPERATION............................6
REMOVAL.............................6
INSTALLATION..........................6
SWITCH
DESCRIPTION..........................7
OPERATION............................7
REMOVAL.............................8
INSTALLATION..........................8
VACUUM RESERVOIR
DESCRIPTION..........................9
OPERATION............................9
DIAGNOSIS AND TESTING - VACUUM
RESERVOIR..........................9
REMOVAL.............................9
INSTALLATION.........................10
SPEED CONTROL
DESCRIPTION
All 3.7L/4.7LGas Engines and/or Diesel With
Automatic Trans.
The speed control system is operated by the use of
a cable and a vacuum controlled servo. On all
engines except diesels, electronic control of the speed
control system is integrated into the Powertrain Con-
trol Module (PCM). If equipped with a diesel engine,
electronic control of the speed control system is inte-
grated into the Engine Control Module (ECM). 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.
5.7L Gas
The speed control system is fully electronically con-
trolled by the Powertrain Control Module (PCM).A
cable and a vacuum controlled servo are not
used. This is a servo-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.
DRSPEED CONTROL 8P - 1

5.9L 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.
OPERATION
When speed control is selected by depressing the
ON switch, the PCM (the ECM with a diesel engine)
allows a set speed to be stored in its 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 selec-
tor be indicating the transmission is in Park or Neu-
tral.
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 (the ECM with a diesel engine).
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 rpm (indicates 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 (the ECM with
a diesel engine).
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 (the ECM with a diesel engine) when the RES/
ACCEL is released. The PCM (the ECM with a diesel
engine) also has a9tap-up9feature in which vehicle
speed increases at a rate of approximately 2 mph for
each momentary switch activation of the RES/AC-
CEL 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
DIAGNOSIS AND TESTING - VACUUM SUPPLY
TEST
3.7L / 4.7L Gas Powered Engines
3.7L/4.7L gas 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.
(3) If vacuum is less than ten inches of mercury,
determine source of leak. Check vacuum line to
engine for leaks. Also check actual engine intake
manifold vacuum. If manifold vacuum does not meet
this requirement, check for poor engine performance
and repair as necessary.
(4) If vacuum line to engine is not leaking, check
for leak at vacuum reservoir. To locate and gain
access to reservoir, refer to Vacuum Reservoir Remov-
al/Installation in this group. Disconnect vacuum line
at reservoir and connect a hand-operated vacuum
pump to reservoir fitting. Apply vacuum. Reservoir
vacuum should not bleed off. If vacuum is being lost,
replace reservoir.
8P - 2 SPEED CONTROLDR
SPEED CONTROL (Continued)

(5) Verify operation of one-way check valve and
check it for leaks.
(a) Locate one-way check valve. The valve is
located in vacuum line between vacuum reservoir
and engine vacuum source. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal the
fitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
5.7 Gas
Vacuum is not used for any part of the speed con-
trol system if equipped with a 5.7L V-8 engine.
5.9L Diesel Engine With Manual Trans.
Vacuum is not used for any part of the speed con-
trol system if equipped with a diesel engine and a
manual transmission.
5.9L Diesel Engines With Automatic Trans.
If equipped with a diesel powered engine and an
automatic transmission, an electric vacuum pump
and vacuum lines are used to supply vacuum to the
speed control servo. A vacuum reservoir is not used.
DIAGNOSIS AND TESTING - ROAD TEST
Perform a vehicle road test to verify reports of
speed control system malfunction. The road test
should include attention to the speedometer. Speed-ometer operation should be smooth and without flut-
ter at all speeds.
Flutter in the speedometer indicates a problem
which might cause surging in the speed control sys-
tem. The cause of any speedometer problems should
be corrected before proceeding. Refer to Instrument
Cluster for speedometer diagnosis.
If a road test verifies a system problem and the
speedometer operates properly, check for:
²A Diagnostic Trouble Code (DTC). If a DTC
exists, conduct tests per the Powertrain Diagnostic
Procedures service manual.
²A misadjusted brake (stop) lamp switch. This
could also cause an intermittent problem.
²Loose, damaged or corroded electrical connec-
tions at the servo (if used). Corrosion should be
removed from electrical terminals and a light coating
of Mopar MultiPurpose Grease, or equivalent,
applied.
²Leaking vacuum reservoir (if used).
²Loose or leaking vacuum hoses or connections (if
used).
²Defective one-way vacuum check valve (if used).
²Secure attachment of both ends of the speed con-
trol servo cable (if used).
²Smooth operation of throttle linkage (if used)
and throttle body air valve.
²Failed speed control servo (if used). Do the servo
vacuum test.
CAUTION: When test probing for voltage or conti-
nuity at electrical connectors, care must be taken
not to damage connector, terminals or seals. If
these components are damaged, intermittent or
complete system failure may occur.
SPECIFICATIONS
TORQUE - SPEED CONTROL
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Servo Mounting Bracket-
to-Servo Nuts7-60
Servo Mounting Bracket-
to-Battery Tray Screws4-30
Speed Control Switch
Mounting Screws1.7 - 15
Vacuum Reservoir
Mounting Nuts3-20
DRSPEED CONTROL 8P - 3
SPEED CONTROL (Continued)

CABLE
DESCRIPTION
The speed control servo cable is connected between
the speed control vacuum servo diaphragm and the
throttle body control linkage. This cable is used with
3.7L/4.7L gas powered engines only. It is also used if
equipped with a 5.9L diesel engine equipped with an
automatic transmission.
A speed control servo cableis not usedif equipped
with either a 5.9L diesel engine equipped with a
manual transmission, or any 5.7L engine/transmis-
sion combinations.
OPERATION
This cable causes the throttle control linkage to
open or close the throttle valve in response to move-
ment of the vacuum servo diaphragm.
REMOVAL
3.7L / 4.7L GAS
(1) Disconnect negative battery cable at battery.
(2) Remove air intake tube at top of throttle body.
The accelerator cable must be partially removed to
gain access to speed control cable.
(3) Hold throttle in wide open position. While held
in this position, slide throttle cable pin (Fig. 1) from
throttle body bellcrank.
(4) Using a pick or small screwdriver, press release
tab (Fig. 2) to release plastic cable mount from
bracket.Press on tab only enough to release
cable from bracket. If tab is pressed too much,
it will be broken.Slide plastic mount (Fig. 2)
towards right side of vehicle to remove throttle cable
from throttle body bracket.
(5) Using finger pressure only, disconnect servo
cable connector (Fig. 3) at throttle body bellcrank pin
by pushing connector off bellcrank pin towards front
of vehicle.DO NOT try to pull connector off per-
pendicular to the bellcrank pin. Connector will
be broken.
(6) Slide speed control cable plastic mount towards
right of vehicle to remove cable from throttle body
bracket (Fig. 4).
(7) Remove servo cable from servo. Refer to Servo
Removal/Installation.
5.9L Diesel Ð Auto. Trans.
(1) Disconnect both negative battery cables at both
batteries.
(2) Remove cable/lever/linkage cover. Refer to
Speed Control Servo Removal/Installation.
(3) Remove (disconnect) servo cable from servo.
Refer to Speed Control Servo Removal/Installation.(4) Using finger pressure only, disconnect end of
servo cable from throttle lever pin by pulling forward
on connector while holding lever rearward (Fig. 5).
DO NOT try to pull connector off perpendicular
to lever pin. Connector will be broken.
(5) Squeeze 2 pinch tabs (Fig. 5) on sides of speed
control cable at mounting bracket and push cable
rearward out of bracket.
Fig. 1 THROTTLE CABLE PIN - 3.7L / 4.7L
1 - THROTTLE CABLE PIN
2 - THROTTLE BODY BELLCRANK
3 - PUSH UP HERE
Fig. 2 THROTTLE CABLE RELEASE TAB - 3.7L /
4.7L
1 - THROTTLE CABLE
2 - RELEASE TAB
3 - PICK OR SCREWDRIVER
4 - PLASTIC CABLE MOUNT
8P - 4 SPEED CONTROLDR