Turn signal switch DODGE RAM 1500 1998 2.G Owner's Manual
[x] Cancel search | Manufacturer: DODGE, Model Year: 1998, Model line: RAM 1500, Model: DODGE RAM 1500 1998 2.GPages: 2627
Page 521 of 2627
ACTUATOR TEST
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.
The instrument cluster actuator test will put the
instrument cluster into its self-diagnostic mode. In
this mode the instrument cluster can perform a self-
diagnostic test that will confirm that the instrument
cluster circuitry, the gauges, and the indicators are
capable of operating as designed. During the actuator
test the instrument cluster circuitry will position
each of the gauge needles at various calibration
points, illuminate all of the segments in the Vacuum
Fluorescent Display (VFD) units, turn all of the indi-
cators on and off again, display any Diagnostic Trou-
ble Code (DTC) information, and display the number
of ignition key cycles that have occurred since the
DTC was detected. It is suggested that a note pad
and pencil be used to write down any fault informa-
tion that is displayed during the test for reference.
Successful completion of the actuator test will con-
firm that the instrument cluster is operational. How-
ever, there may still be a problem with the PCI data
bus, the Powertrain Control Module (PCM), the
Engine Control Module (ECM), the Front Control
Module (FCM), the Transmission Control Module
(TCM), the Transfer Case Control Module (TCCM),
the Airbag Control Module (ACM), the Controller
Anti-lock Brake (CAB), or the inputs to one of these
electronic control modules. Use a DRBIIItscan toolto diagnose these components. Refer to the appropri-
ate diagnostic information.
(1) Begin the test with the ignition switch in the
Off position.
(2) Depress the odometer/trip odometer switch but-
ton.
(3) While still holding the odometer/trip odometer
switch button depressed, turn the ignition switch to
the On position, but do not start the engine.
(4) Release the odometer/trip odometer switch but-
ton.
(5) The instrument cluster will simultaneously
illuminate all of the operational segments in both
VFD units, perform a bulb check of each operational
LED indicator. The VFD segments and LED indica-
tors remain illuminated as each gauge needle is
swept to several calibration points and back. If a
VFD segment or an LED indicator fails to illuminate,
or if a gauge needle fails to sweep through the cali-
bration points and back during this test, the instru-
ment cluster must be replaced. Following these tests,
the actuator test will proceed as described in Step 6.
(6) The text ªC Codeº is displayed in the odometer
VFD for about three seconds. If there is no stored
fault information, the display will show two pairs of
zeroes in the format ª00º ª00º, which indicate that
the display of fault information is done. If there is
stored fault information, two sets of two-digit alpha
and alpha-numeric fault codes will appear in the
odometer display for a three second interval. The
first pair of digits represents a Diagnostic Trouble
Code (DTC), or fault code for the instrument cluster.
The second pair of digits is a counter for the number
of ignition key cycles that have occurred since the
displayed DTC was set. The instrument cluster will
continue to display additional sets of two pairs of dig-
its at three second intervals until all of the stored
codes have been displayed, which is again signaled
by a code of ª00º ª00º. Refer to the Instrument Clus-
ter Failure Message table for a description of each
fault code that the instrument cluster displays. If an
instrument cluster fault is displayed, use a DRBIIIt
scan tool to diagnose the problem. Refer to the appro-
priate diagnostic information.
INSTRUMENT CLUSTER FAILURE MESSAGE
Fault Code Description Correction
01 Airbag warning indicator output circuit shorted. Refer to the appropriate diagnostic information.
02 Airbag warning indicator output circuit open. Refer to the appropriate diagnostic information.
03 ABS indicator output circuit shorted. Refer to the appropriate diagnostic information.
04 ABS indicator output circuit open. Refer to the appropriate diagnostic information.
05 MIL indicator output circuit shorted. Refer to the appropriate diagnostic information.
06 MIL indicator output circuit open. Refer to the appropriate diagnostic information.
8J - 12 INSTRUMENT CLUSTERDR
INSTRUMENT CLUSTER (Continued)
Page 538 of 2627
tery saver) timed interval expires, whichever occurs
first.
²Actuator Test- Each time the cluster is put
through the actuator test, the high beam indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the LED and the cluster control circuitry.
The instrument cluster continually monitors the
headlamp switch and the multi-function switch to
determine the proper headlamp low beam and high
beam control. The instrument cluster then sends the
proper low beam and high beam lamp-on and lamp-
off messages to the Front Control Module (FCM) over
the Programmable Communications Interface (PCI)
data bus and turns the high beam indicator on or off
accordingly. For further diagnosis of the high beam
indicator or the instrument cluster circuitry that con-
trols the indicator, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND
TESTING). For proper diagnosis of the headlamps, or
the headlamp switch and multi-function switch
inputs to the instrument cluster that control the high
beam indicator, a DRBIIItscan tool is required.
Refer to the appropriate diagnostic information.
LAMP OUT INDICATOR
DESCRIPTION
A lamp out indicator is standard equipment on all
instrument clusters (Fig. 20). The lamp out indicator
consists of the words ªLAMP OUTº, which appear in
the lower portion of the odometer/trip odometer Vac-
uum-Fluorescent Display (VFD) unit. The VFD is sol-
dered onto the cluster electronic circuit board and is
visible through a window with a smoked clear lens
located on the lower edge of the tachometer gauge
dial face of the cluster overlay. The dark lens over
the VFD prevents the indicator from being clearly
visible when it is not illuminated. The words ªLAMP
OUTº appear in an amber color and at the same
lighting level as the odometer/trip odometer informa-
tion when they are illuminated by the instrument
cluster electronic circuit board. The lamp out indica-
tor is serviced as a unit with the VFD in the instru-
ment cluster.
OPERATION
The lamp out indicator gives an indication to the
vehicle operator when an exterior lamp has failed.
This indicator is controlled by the instrument clustercircuit board based upon cluster programming and
electronic messages received by the cluster from the
Front Control Module (FCM) over the Programmable
Communications Interface (PCI) data bus. The lamp
out indicator is completely controlled by the instru-
ment cluster logic circuit, and that logic will only
allow this indicator to operate when the instrument
cluster receives a battery current input on the fused
ignition switch output (run-start) circuit. Therefore,
the indicator will always be off when the ignition
switch is in any position except On or Start. The
indicator only illuminates when it is switched to
ground by the instrument cluster circuitry. The
instrument cluster will turn on the lamp out indica-
tor for the following reasons:
²Lamp Out Indicator Lamp-On Message-
Each time the cluster receives a lamp out indicator
lamp-on message from the FCM indicating that an
inoperative headlamp (low or high beam), turn signal
lamp, or brake lamp (excluding Center High
Mounted Stop Lamp [CHMSL]) circuit has been
detected, the lamp out indicator is illuminated. The
indicator remains illuminated until the cluster
receives a lamp out indicator lamp-off message from
the FCM 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 lamp out indicator will
be turned on, then off again during the VFD portion
of the test to confirm the functionality of the VFD
and the cluster control circuitry.
The FCM monitors each of the headlamp, turn sig-
nal lamp, and brake lamp (except CHMSL) circuits to
determine the condition of these exterior lamps. The
FCM then sends the proper lamp out indicator
lamp-on and lamp-off messages to the instrument
cluster. For further diagnosis of the lamp out indica-
tor or the instrument cluster circuitry that controls
the indicator, (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the exterior lighting system
circuits, the FCM, the PCI data bus, or the electronic
message inputs to the instrument cluster that control
the lamp out indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
Fig. 20 Lamp Out Indicator
DRINSTRUMENT CLUSTER 8J - 29
HIGH BEAM INDICATOR (Continued)
Page 549 of 2627
required. Refer to the appropriate diagnostic infor-
mation.
TRANS TEMP INDICATOR
DESCRIPTION
A transmission over-temperature indicator is stan-
dard equipment on all instrument clusters (Fig. 31).
However, on vehicles not equipped with an optional
automatic transmission, this indicator is electroni-
cally disabled. The transmission over-temperature
indicator is located on the left side of the instrument
cluster, to the left of the fuel gauge. The transmission
over-temperature indicator consists of a stencil-like
cutout of the words ªTRANS TEMPº 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
Light Emitting Diode (LED) behind the cutout in the
opaque layer of the overlay causes the ªTRANS
TEMPº text to appear in red through the translucent
outer layer of the overlay when the indicator is illu-
minated from behind by the LED, which is soldered
onto the instrument cluster electronic circuit board.
The transmission over-temperature indicator is ser-
viced as a unit with the instrument cluster.
OPERATION
The transmission over-temperature indicator gives
an indication to the vehicle operator when the trans-
mission fluid temperature is excessive, which may
lead to accelerated transmission component wear or
failure. 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 Powertrain Control Module
(PCM) over the Programmable Communications
Interface (PCI) data bus. The transmission over-tem-
perature indicator Light Emitting Diode (LED) is
completely controlled by the instrument cluster logic
circuit, and that logic will only allow this indicator to
operate when the instrument cluster receives a bat-
tery current input on the fused ignition switch out-
put (run-start) circuit. Therefore, the LED will
always be off when the ignition switch is in any posi-
tion except On or Start. The LED only illuminates
when it is provided a path to ground by the instru-
ment cluster transistor. The instrument cluster will
turn on the transmission over-temperature indicator
for the following reasons:²Bulb Test- Each time the ignition switch is
turned to the On position the transmission over-tem-
perature indicator is illuminated for about two sec-
onds as a bulb test.
²Trans Over-Temp Lamp-On Message- Each
time the cluster receives a trans over-temp lamp-on
message from the PCM indicating that the transmis-
sion fluid temperature is 135É C (275É F) or higher,
the indicator will be illuminated and a single chime
tone is sounded. The indicator remains illuminated
until the cluster receives a trans over-temp lamp-off
message from the PCM, or until the ignition switch
is turned to the Off position, whichever occurs first.
The chime tone feature will only repeat during the
same ignition cycle if the transmission over-tempera-
ture indicator is cycled off and then on again by the
appropriate trans over-temp messages from the PCM.
²Actuator Test- Each time the cluster is put
through the actuator test, the transmission over-tem-
perature indicator will be turned on, then off again
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 transmission
temperature sensor to determine the transmission
operating condition. The PCM then sends the proper
trans over-temp lamp-on or lamp-off messages to the
instrument cluster. If the instrument cluster turns on
the transmission over-temperature indicator due to a
high transmission oil temperature condition, it may
indicate that the transmission and/or the transmis-
sion cooling system are being overloaded or that they
require service. For further diagnosis of the trans-
mission over-temperature indicator or the instrument
cluster circuitry that controls the LED, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). For proper diagnosis of the
transmission temperature sensor, the PCM, the PCI
data bus, or the electronic message inputs to the
instrument cluster that control the transmission
over-temperature indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic infor-
mation.
TURN SIGNAL INDICATOR
DESCRIPTION
Two turn signal indicators, one right and one left,
are standard equipment on all instrument clusters
(Fig. 32). The turn signal indicators are located near
Fig. 31 Transmission Overtemp Indicator
Fig. 32 Turn Signal Indicators
8J - 40 INSTRUMENT CLUSTERDR
TOW/HAUL INDICATOR (Continued)
Page 550 of 2627
the upper edge of the instrument cluster, between
the speedometer and the tachometer. Each turn sig-
nal indicator consists of a stencil-like cutout of the
International Control and Display Symbol icon for
ªTurn Warningº in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents these icons from being clearly visi-
ble when they are not illuminated. A green Light
Emitting Diode (LED) behind each turn signal indi-
cator cutout in the opaque layer of the overlay causes
the icon to appear in green through the translucent
outer layer of the overlay when the indicator is illu-
minated from behind by the LED, which is soldered
onto the instrument cluster electronic circuit board.
The turn signal indicators are serviced as a unit with
the instrument cluster.
OPERATION
The turn signal indicators give an indication to the
vehicle operator that the turn signal (left or right
indicator flashing) or hazard warning (both left and
right indicators flashing) have been selected and are
operating. These indicators are controlled by transis-
tors on the instrument cluster electronic circuit board
based upon the cluster programming, a hard wired
multiplex input received by the cluster from the turn
signal and hazard warning switch circuitry of the
multi-function switch on the turn/hazard switch mux
circuit, and electronic messages received from the
Front Control Module (FCM) over the Programmable
Communications Interface (PCI) data bus. Each turn
signal indicator Light Emitting Diode (LED) is com-
pletely controlled by the instrument cluster logic cir-
cuit, and that logic will allow this indicator to
operate whenever the instrument cluster receives a
battery current input on the fused B(+) circuit.
Therefore, each LED can be illuminated regardless of
the ignition switch position. The LED only illumi-
nates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the turn signal indicators for the follow-
ing reasons:
²Turn Signal-On Input- Each time the cluster
detects a turn signal-on input from the turn signal
switch circuitry of the multi-function switch on the
turn/hazard switch mux circuit, the requested turn
signal lamps and turn signal indicator will be flashed
on and off, and an electromechanical relay soldered
onto the cluster electronic circuit board will produce
a clicking sound to emulate a conventional turn sig-
nal flasher. The turn signals and the turn signal
indicators continue to flash on and off until the clus-
ter receives a turn signal-off input from the multi-
function switch, or until the ignition switch is turned
to the Off position, whichever occurs first.²Hazard Warning-On Input- Each time the
cluster detects a hazard warning-on input from the
hazard warning switch circuitry of the multi-function
switch on the turn/hazard switch mux circuit, all of
the turn signal lamps and both turn signal indicators
will be flashed on and off, and an electromechanical
relay soldered onto the cluster electronic circuit
board will produce a clicking sound to emulate a con-
ventional hazard warning flasher. The turn signals
and the turn signal indicators continue to flash on
and off until the cluster receives a hazard warning-
off input from the multi-function switch.
²Lamp Out Mode- The instrument cluster also
sends electronic turn signal on and off messages to
the FCM over the PCI data bus, and the FCM
flashes the appropriate exterior turn signal lamps. If
the FCM detects an inoperative turn signal lamp or
circuit, it increases the flash rate for the remaining
operative turn signals and sends an electronic mes-
sage back to the instrument cluster. The instrument
cluster then increases the flash rate of the turn sig-
nal indicator(s) and the clicking rate of the electro-
mechanical relay to provide an indication of the
problem to the vehicle operator.
²Actuator Test- Each time the cluster is put
through the actuator test, the turn signal indicators
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of each LED and the cluster control circuitry.
The instrument cluster continually monitors the
multi-function switch and electronic messages from
the FCM to determine the proper turn signal and
hazard warning system control. For further diagnosis
of the turn signal indicators or the instrument clus-
ter circuitry that controls the indicators, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING). For proper diagnosis of the
turn signal and hazard warning system, the multi-
function switch, the FCM, the PCI data bus, or the
electronic message inputs to the instrument cluster
that control the turn signal indicators, a DRBIIIt
scan tool is required. Refer to the appropriate diag-
nostic information.
UPSHIFT INDICATOR
DESCRIPTION
An upshift indicator is standard equipment on all
instrument clusters (Fig. 33). However, on vehicles
not equipped with a manual transmission, this indi-
Fig. 33 Upshift Indicator
DRINSTRUMENT CLUSTER 8J - 41
TURN SIGNAL INDICATOR (Continued)
Page 557 of 2627
MARKER LAMP UNIT
REMOVAL
REMOVAL - FENDER MARKER LAMP......17
REMOVAL - TAILGATE MARKER LAMP.....18
INSTALLATION
INSTALLATION - FENDER MARKER LAMP . . 18
INSTALLATION - TAILGATE MARKER LAMP . 18
MULTI-FUNCTION SWITCH
DESCRIPTION - TURN SIGNAL SYSTEM.....18
OPERATION - TURN SIGNAL SYSTEM.......18
DIAGNOSIS AND TESTING - MULTI-
FUNCTION SWITCH...................18
REMOVAL.............................19
INSTALLATION.........................19
PARK LAMP RELAY
DESCRIPTION.........................20
OPERATION...........................20
DIAGNOSIS AND TESTING - PARK LAMP
RELAY..............................20
REMOVAL.............................21
INSTALLATION.........................21
PARK/TURN SIGNAL LAMP
REMOVAL.............................21
INSTALLATION.........................21
TAIL LAMP
REMOVAL
REMOVAL - WITH CARGO BOX..........22REMOVAL - WITHOUT CARGO BOX.......22
INSTALLATION
INSTALLATION - WITH CARGO BOX.......22
INSTALLATION - WITHOUT CARGO BOX . . . 22
TAIL LAMP UNIT
REMOVAL
REMOVAL - WITH CARGO BOX..........22
REMOVAL - WITHOUT CARGO BOX.......23
INSTALLATION
INSTALLATION - WITH CARGO BOX.......23
INSTALLATION - WITHOUT CARGO BOX . . . 23
TRAILER TOW WIRING
DESCRIPTION.........................24
TURN LAMP
REMOVAL
REMOVAL - WITH CARGO BOX..........24
REMOVAL - WITHOUT CARGO BOX.......24
INSTALLATION
INSTALLATION - WITH CARGO BOX.......24
INSTALLATION - WITHOUT CARGO BOX . . . 24
UNDERHOOD LAMP
REMOVAL.............................25
INSTALLATION.........................25
UNDERHOOD LAMP UNIT
REMOVAL.............................25
INSTALLATION.........................25
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION
The exterior lighting system for this model include
the following components:
²Backup Lamps
²Brake Lamps
²Daytime Running Lamps
²Front Fog Lamps
²Hazard Warning Lamps
²Headlamps
²Park Lamps
²Turn Signal Lamps
Other components of the exterior lighting system
for this model include:
²Backup Lamp Switch
²Brake Lamp Switch
²Front Control Module
²Front Fog Lamp Relay
²Hazard Switch
²Multi-Function Switch
²Park Lamp Relay
²Trailer Tow Connectors
Some of the interior and exterior lighting functions
are governed by the front control module. The head-
lamp, dome, and door ajar switchs provide signals to
the instrument cluster. The instrument cluster sends
a J1850 message to the front control module to
enable the necessary components for illumination.Hard wired circuitry connects the exterior lighting
system components to the electrical system of the
vehicle. Refer to the appropriate wiring information.OPERATION
DAYTIME RUNNING LAMPS
Power is reduced using pulse-width modulation to
the high beams, where by the power is switched on
and off rapidly instead of remaining on continuously.
The duration and interval of the power pulses is pro-
grammed into the Front Control Module (FCM).
HEADLAMP SYSTEM
The instrument cluster monitors both the multi-
plexed headlamp and multifunction switches. The
instrument cluster transmits a J1850 bus message to
the front control module (FCM) to activate the head-
lamps. The headlamp system will default to head-
lamps ON position when ignition switch is ON and
when an open or short circuit failure occurs on the
headlamp switch input to the instrument cluster. The
system will return to normal operation when the
open or short is repaired. A fault will be reported by
the Instrument Cluster when a failure occurs on the
dimmer or headlamp switch input.
If the exterior lamps are ON, and the headlamp
switch is in any position other than OFF, with the
ignition switch OFF (LOCK) after 5 minutes, the
8L - 2 LAMPS/LIGHTING - EXTERIORDR
Page 558 of 2627
Instrument Cluster transmits a message via J1850
informing the the FCM. The FCM will then turn off
the headlamps, park lamps and fog lamps. This fea-
ture (load shed) prevents the vehicle battery from
being discharged when the vehicle lights have been
left ON.
HEADLAMP TIME DELAY SYSTEM
The headlamp time delay system is activated by
turning the headlamps ON (high or low beam) while
the engine is running, turning the ignition switch
OFF, and then turning the headlamp switch OFF
within 45 seconds. The system will not activate if
more than 45 seconds elapse between ignition switch
OFF and headlamp switch OFF. The FCM will allow
the headlamps to remain ON for 60 seconds (config-
urable) before they automatically turn off (If the key
is in the ignition during the headlamp time delay
mode, then the headlamps including panel dimming
will be ON).
LAMP OUTAGE
If one or more of the following lamps (Low and/or
High beams, Brake and/or Turn Signal) are out, then
a ªlamps outº indicator located in the cluster will
illuminate.
OPTICAL HORN/HIGH BEAMS
When the multiplexed multifunction switch is
pulled to the first detent (optical horn) signal, the
headlamps are ON, the Instrument Cluster shall
send a message via J1850 to the FCM to turn on the
headlamps drivers to illuminate all four filaments
(Low and High beams). When the multifunction
switch is pulled to the second detent (high beam) sig-
nal and the headlamps are ON, the Instrument Clus-
ter shall send a message via J1850 to the FCM to
turn on the headlamps drivers. The High Beams are
illuminated and the Low Beams and Fog Lamps (if
ON) are extinguished. If the headlamps were in the
high beam configuration when power was removedfrom the headlamps, the headlamps will return to
their last state prior to being shut off.
DIAGNOSIS AND TESTING - LAMPS/LIGHTING
- EXTERIOR
WARNING: EYE PROTECTION SHOULD BE USED
WHEN SERVICING GLASS COMPONENTS. PER-
SONAL INJURY CAN RESULT.
CAUTION: Do not touch the glass of halogen bulbs
with fingers or other possibly oily surface, reduced
bulb life will result. Do not use bulbs other than
those indicated in the Bulb Application table. Dam-
age to lamp and/or Daytime Running Lamp Module
can result. Do not use fuses, circuit breakers or
relays having greater amperage value than indi-
cated on the fuse panel or in the Owners Manual.
When a vehicle experiences problems with the
headlamp system, verify the condition of the battery
connections, fuses, charging system, headlamp bulbs,
wire connectors, relay, multifunction switch, and
headlamp switch. Refer to the appropriate wiring
information.
Each vehicle is equipped with various lamp assem-
blies. A good ground is necessary for proper lighting
operation. Grounding is provided by the lamp socket
when it comes in contact with the metal body, or
through a separate ground wire.
When changing lamp bulbs check the socket for
loose pin connections and corrosion. Repair as neces-
sary.
When it is necessary to remove components to ser-
vice another, it should not be necessary to apply
excessive force or bend a component to remove it.
Before damaging a trim component, verify hidden
fasteners or captured edges are not holding the com-
ponent in place.
DRLAMPS/LIGHTING - EXTERIOR 8L - 3
LAMPS/LIGHTING - EXTERIOR (Continued)
Page 565 of 2627
Vehicles equipped with the speed control option use
a dual function brake lamp switch. The PCM moni-
tors the state of the dual function brake lamp switch.
The brake switch is equipped with three sets of
contacts, one normally open and the other two nor-
mally closed (brakes disengaged). The PCM sends a
12 volt signal to one of the normally closed contacts
in the brake switch, which is returned to the PCM as
a brake switch state signal. With the contacts closed,
the 12 volt signal is pulled to ground causing the sig-
nal to go low. The low voltage signal, monitored by
the PCM, indicates that the brakes are not applied.
When the brakes are applied, the contacts open,
causing the PCM's output brake signal to go high,
disengaging the speed control, cutting off PCM power
to the speed control solenoids.
The second set of normally closed contacts supplies
12 volts from the PCM any time speed control is
turned on. Through the brake switch, voltage is
routed to the speed control servo solenoids. The
speed control solenoids (vacuum, vent and dump) are
provided this voltage any time the speed control is
ON and the brakes are disengaged.
When the driver applies the brakes, the contacts
open and voltage is interrupted to the solenoids. The
normally open contacts are fed battery voltage. When
the brakes are applied, battery voltage is supplied to
the brake lamps.
The brake lamp switch can only be adjusted once.
That is at the initial installation of the switch. If the
switch is not adjusted properly or has been removed,
a new switch must be installed and adjusted.
DIAGNOSIS AND TESTING - BRAKE LAMP
SWITCH
The brake lamp switch can be tested with an ohm-
meter. The ohmmeter is used to check continuity
between the pin terminals (Fig. 4).
SWITCH CIRCUIT IDENTIFICATION
²Terminals 1 and 2: brake lamp circuit
²Terminals 3 and 4: RWAL/ABS module and Pow-
ertrain Control Module (PCM) circuit
²Terminals 5 and 6: speed control circuit
SWITCH CONTINUITY TEST
NOTE: Disconnect switch harness before testing
switch continuity.
With switch plunger extended, attach test leads to
pins 1 and 2. Replace switch if meter indicates no
continuity.
With switch plunger retracted, attach test leads to
pins 3 and 4. Replace switch if meter indicates no
continuity.With switch plunger retracted, attach test leads to
pins 5 and 6. Replace switch if meter indicates no
continuity.
REMOVAL
(1) Disconnect the switch harness (Fig. 5).
(2) Press and hold the brake pedal in applied posi-
tion.
(3) Rotate the switch counterclockwise about 30É to
align the switch lock tab with the notch in bracket.
(4) Pull the switch rearward out of the mounting
bracket and release the brake pedal.
Fig. 4 Brake Lamp Switch Terminal Identification
1 - TERMINAL PINS
2 - PLUNGER TEST POSITIONS
Fig. 5 Brake Lamp Switch & Bracket
1 - RELEASE LEVER
2 - BRACKET
3 - BRAKE PEDAL SUPPORT
4 - BRAKE LAMP SWITCH
8L - 10 LAMPS/LIGHTING - EXTERIORDR
BRAKE LAMP SWITCH (Continued)
Page 569 of 2627
(1) Position the front fog lamp relay to the proper
receptacle in the Power Distribution Center (PDC).
(2) Align the front fog lamp relay terminals with
the terminal cavities in the PDC.
(3) Press firmly and evenly on the top of the front
fog lamp relay until the terminals are fully seated in
the PDC.
(4) Reconnect the battery negative cable.
HAZARD SWITCH
DESCRIPTION
The hazard switch is activated by a push button
located in the multifunction switch on the top of the
steering column between the steering wheel and
instrument cluster.
The hazard warning system allows the vehicle
operator to provide other vehicle operators in the
near proximity an optical indication that the vehicle
is disabled or an obstacle to traffic flow. The hazard
warning system has battery voltage at all times,
regardless of ignition position.
OPERATION
The instrument cluster monitors the multiplexed
multifunction switch operation. When the hazard
warning switch is activated, the instrument cluster
will send a J1850 bus message to the Front Control
Module (FCM), then activate the two turn signal
indicators and audible click in the instrument clus-
ter.
The FCM will then activate the necessary relays in
the Power Distribution Center (PDC) to begin flash-
ing both the front and rear turn signal indicator
lamps.
HEADLAMP
REMOVAL
(1) Disconnect and isolate the negitive battery
cable.
(2) Remove the headlamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/HEAD-
LAMP UNIT - REMOVAL).
(3) Seperate the socket from the headlamp unit.
INSTALLATION
CAUTION: Do Not Touch the bulb glass with fingers
or other oily surfaces. Reduced bulb life will result.
(1) Install the socket into the headlamp unit.
(2) Install the headlamp unit (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/HEAD-
LAMP UNIT - INSTALLATION).(3) Connect the negitive battery cable.
HEADLAMP SWITCH
DESCRIPTION
The multiplexed headlamp switch is located on the
instrument panel. The headlamp switch controls the
parking lamps, fog lamps and the headlamps. A sep-
arate switch in the module controls the interior
lamps and instrument cluster illumination. This
switch also contains a rheostat for controlling the
illumination level of the cluster lamps.
OPERATION
The multiplexed headlamp switch has an off, park-
ing lamp, fog lamp and a headlamp on position. High
beams are controlled by the multiplexed multifunc-
tion switch on the steering column. The fog lamps
are illuminated by pulling back on the headlamp
switch knob when in the parking lamp or headlamp
ON position.The headlamp switch cannot be
repaired. It must be replaced.
The Instrument Cluster monitors the headlamp
and multifunction switch operation. When the head-
lamp switch is rotated to the parking lamp or On
position the Instrument Cluster sends a J1850 mes-
sage to the Front Control Module, which is mated to
the power distribution center to become the Inte-
grated Control Module, to illuminate the appropriate
bulbs. When the multifunction switch is activated to
the optical horn or high beam position the Instru-
ment Cluster illuminates the high beam indicator
and sends a J1850 message to the Front Control
Module to illuminate the appropriate bulbs.
REMOVAL
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) Disconnect and isolate the battery negative
cable.
8L - 14 LAMPS/LIGHTING - EXTERIORDR
FOG LAMP RELAY (Continued)
Page 570 of 2627
(2) Remove the left instrument panel bezel. (Refer
to 23 - BODY/INSTRUMENT PANEL/CLUSTER
BEZEL - REMOVAL).
(3) Disconnect the harness connector.
(4) Remove the screws that secure the headlamp
switch to the instrument panel bezel (Fig. 10).
(5) Remove the headlamp switch from the instru-
ment panel bezel.
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 headlamp switch to the left instru-
ment panel bezal and secure with screws.Tighten the
screws to 2.2 N´m (20 in. lbs.).(2) Reconnect the instrument panel wire harness
connector for the headlamp switch.
(3) Position the left instrument panel bezal on to
the instrument panel.
(4) Install the cluster bezel onto the instrument
panel (Fig. 10).
(5) Connect the battery negative cable.
HEADLAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the push pins attaching the seal to the
fender.
(3) Remove the bolts attaching the headlamp unit
to the fender (Fig. 11).
(4) Remove the bulb sockets from the headlamp
unit
(5) Separate headlamp unit from vehicle.
INSTALLATION
CAUTION: Do not touch the bulb glass with fingers
or other oily surfaces. Reduced bulb life will result.
(1) Install the bulb sockets for the front park/turn
signal and headlamp.
(2) Position headlamp unit in inner fender panel.
Fig. 10 Headlamp Switch Removal
1 - DASH BOARD
2 - HEADLAMP SWITCH
3 - INSTRUMENT PANEL BEZAL
Fig. 11 Headlamp - Typical
1 - SEAL
2 - PUSH PIN
3 - SCREW
4 - HEADLAMP UNIT
DRLAMPS/LIGHTING - EXTERIOR 8L - 15
HEADLAMP SWITCH (Continued)
Page 573 of 2627
REMOVAL - TAILGATE MARKER LAMP
(1) Remove the two screws that secure the lens
assembly to the tailgate (Fig. 15).
(2) Turn the bulb sockets counterclockwise a quar-
ter turn and remove the bulb sockets from the lens
assembly.
INSTALLATION
INSTALLATION - FENDER MARKER LAMP
(1) Install the bulb socket to the lens assembly.
Turn the bulb socket a quarter turn clockwise.
(2) Position the lens assembly against the fender.
Using firm pressure, push the lens assembly into the
fender.
INSTALLATION - TAILGATE MARKER LAMP
(1) Install the bulb sockets into the lens assembly.
Turn the bulb sockets a quarter turn clockwise.(2) Position the lens assembly to the tailgate.
Install and tighten the two screws securely.
MULTI-FUNCTION SWITCH
DESCRIPTION - TURN SIGNAL SYSTEM
The multi-function switch is a resistive MUX
switch that is monitored by the Instrument Cluster.
The turn signals are actuated with the lever on
Multi-Function Switch. The signals are automatically
turned off by a canceling cam (two lobes molded to
the back of the clock spring mechanism). The cam
comes in contact with the cancel actuator on the turn
signal (multi-function) switch assembly. Either cam
lobe, pushing on the cancel actuator, returns the
switch to the OFF position.
OPERATION - TURN SIGNAL SYSTEM
The Instrument Cluster monitors the multiplexed
multifunction switch. In a turning event the Instru-
ment Cluster senses a change in the turn signal
lever and illuminates the appropriate turn signal
indicator. At the same time, the Instrument Cluster
will send a J1850 message on the PCI bus to the
Front Control Module (FCM). The FCM will respond
by activating the appropriate relay in the Power Dis-
tribution Center.
A chime will sound after the turn is completed if
vehicle has traveled a distance of approximately 1.0
mile and a speed of 15 mph, with the turn signal ON.
DIAGNOSIS AND TESTING - MULTI-FUNCTION
SWITCH
To test the turn signal, headlamp beam select and
optical horn portion of the multi-function switch:
(1) Remove the multi-function switch, refer to
Electrical, Lamps/Lighting - Exterior, Multi-Function
Switch, Removal, and Installation.
(2) Using an ohmmeter check the resistance read-
ings between multi-function switch pins. Refer to
Wiring Diagrams for proper pin numbers and the
MULTI-FUNCTION SWITCH TESTS table.
MULTI-FUNCTION SWITCH TESTS
EXTERIOR LIGHTING FUNCTIONS
SWITCH POSITION CONNECTOR PINS RESISTANCE (OHMS)
Off 1 - 2 Open
Headlamp High Beams On 1 - 2 518 - 575
Hazard 3 - 2 115 - 128
Fig. 15 Tailgate Marker Lamp Housing
1 - RETAINING NUT (2)
2 - TAILGATE
3 - WIRING HARNESS AND BULB SOCKET
4 - SCREW (2)
5 - LENS ASSEMBLY
8L - 18 LAMPS/LIGHTING - EXTERIORDR
MARKER LAMP UNIT (Continued)