ignition DODGE RAM 2001 Service Repair Manual

above the temperature gauge. The voltage gauge con-
sists of a movable gauge needle or pointer controlled
by the instrument cluster circuitry and a fixed 90
degree scale on the cluster overlay that reads left-to-
right from 8 volts to 18 volts. An International Con-
trol and Display Symbol icon for ªBattery Charging
Conditionº is located directly below the lowest grad-
uation of the gauge scale. The voltage gauge graphics
are white against a black field except for a single red
graduation at each end of the gauge scale, making
them clearly visible within the instrument cluster in
daylight. When illuminated from behind by the panel
lamps dimmer controlled cluster illumination lighting
with the exterior lamps turned On, the white graph-
ics appear blue-green and the red graphics appear
red. The orange gauge needle is internally illumi-
nated. Gauge illumination is provided by replaceable
incandescent bulb and bulb holder units located on
the instrument cluster electronic circuit board. The
voltage gauge is serviced as a unit with the instru-
ment cluster.
OPERATION
The voltage gauge gives an indication to the vehi-
cle operator of the electrical system voltage. This
gauge is controlled by the instrument cluster circuit
board based upon the cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Chrysler
Collision Detection (CCD) data bus. The voltage
gauge is an air core magnetic unit that receives bat-
tery current on the instrument cluster electronic cir-
cuit board through the fused ignition switch output
(st-run) circuit whenever the ignition switch is in the
On or Start positions. The cluster is programmed to
move the gauge needle back to the low end of the
scale after the ignition switch is turned to the Off
position. The instrument cluster circuitry controls
the gauge needle position and provides the following
features:
²Charge Fail Message- Each time the cluster
receives a message from the PCM indicating a charge
fail condition (system voltage is 10.8 volts or lower),
the gauge needle is moved to the 8 volt graduation
on the gauge scale and the check gauges indicator is
illuminated. The gauge needle remains on the 8 volt
graduation and the check gauges indicator remains
illuminated until the cluster receives a message from
the PCM indicating there is no charge fail condition
(system voltage is 10.9 volts or higher, but lower
than 16.7 volts), or until the ignition switch is turned
to the Off position, whichever occurs first. On models
equipped with the optional diesel engine, the instru-
ment cluster is programmed to support the voltmeter
gauge needle above the low end of normal graduation
and suppress the check gauges indicator operationuntil ten seconds after the engine intake manifold air
heater has completed its cycle.
²Voltage High Message- Each time the cluster
receives a message from the PCM indicating a volt-
age high condition (system voltage is 16.7 volts or
higher), the gauge needle is moved to the 18 volt
graduation on the gauge scale and the check gauges
indicator is illuminated. The gauge needle remains
on the 18 volt graduation and the check gauges indi-
cator remains illuminated until the cluster receives a
message from the PCM indicating there is no voltage
high condition (system voltage is 16.6 volts or lower,
but higher than 10.9 volts), or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Message Failure- If the cluster fails to receive
a system voltage message, it will hold the gauge nee-
dle 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 system voltage
to control the generator output. The PCM then sends
the proper system voltage messages to the instru-
ment cluster. For further diagnosis of the voltage
gauge or the instrument cluster circuitry that con-
trols the gauge, (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING). If
the instrument cluster turns on the check gauges
indicator due to a charge fail or voltage high condi-
tion, it may indicate that the charging system
requires service. For proper diagnosis of the charging
system, the CCD data bus, or the message inputs to
the instrument cluster that control the voltage
gauge, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
WAIT-TO-START INDICATOR
DESCRIPTION
A wait-to-start indicator is standard equipment on
all instrument clusters, but is only functional in vehi-
cles equipped with an optional diesel engine. The
wait-to-start indicator is located near the lower edge
of the instrument cluster overlay, to the right of cen-
ter. The wait-to-start indicator consists of a stenciled
cutout of the text ªWAIT TO STARTº in the opaque
layer of the cluster overlay. The dark outer layer of
the overlay prevents the indicator from being clearly
visible when it is not illuminated. A red lens located
8J - 34 INSTRUMENT CLUSTERBR/BE
VOLTAGE GAUGE (Continued)

behind the cutout causes the ªWAIT TO STARTº text
to appear in red through the translucent outer layer
of the overlay when the indicator is illuminated from
behind by a Light Emitting Diode (LED) that is sol-
dered onto the instrument cluster electronic circuit
board. The wait-to-start indicator is serviced as a
unit with the instrument cluster.
OPERATION
The wait-to-start indicator gives an indication to
the vehicle operator when the diesel engine intake
air heater is energized in its preheat operating mode.
This indicator is controlled by a hard wired input to
the instrument cluster from the Engine Control Mod-
ule (ECM). The wait-to-start indicator Light Emitting
Diode (LED) receives battery current on the instru-
ment 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 igni-
tion switch is in any position except On or Start. The
indicator LED only illuminates when it is switched to
ground by the input from the ECM. The ECM will
turn on the wait-to-start indicator by pulling the
wait-to-start indicator driver circuit to ground each
time the ignition switch is turned to the On or Start
positions. The indicator then remains illuminated
until the ECM detects that the air within the intake
manifold is the proper temperature to ensure reliable
and efficient engine starting, until the ECM detects
that the engine is running, or until the ignition
switch is turned to the Off position, whichever occurs
first.
The ECM continually monitors the intake manifold
air temperature sensor, the Manifold Absolute Pres-
sure (MAP) sensor, and many other vehicle condi-
tions to determine when the wait-to-start indicator
should be illuminated. For proper diagnosis of the
wait-to-start indicator, the ECM, or the inputs the
ECM uses to control the wait-to-start indicator oper-
ation, a DRBIIItscan tool is required. Refer to the
appropriate diagnostic information.
WASHER FLUID INDICATOR
DESCRIPTION
A washer fluid indicator is standard equipment on
all instrument clusters. The washer fluid indicator is
located near the lower edge of the instrument cluster
overlay, to the right of center. The washer fluid indi-
cator consists of a stenciled cutout of the words
ªLOW WASHERº in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents the indicator from being clearly vis-
ible when it is not illuminated. An amber lens behindthe cutout in the opaque layer of the overlay causes
the ªLOW WASHERº text to appear in amber
through the translucent outer layer of the overlay
when it is illuminated from behind by a Light Emit-
ting Diode (LED) soldered onto the instrument clus-
ter electronic circuit board. The washer fluid
indicator is serviced as a unit with the instrument
cluster.
OPERATION
The washer fluid indicator gives an indication to
the vehicle operator when the fluid level in the
washer fluid reservoir is low. This indicator is con-
trolled by a transistor on the instrument cluster elec-
tronic circuit board based upon cluster programming
and a hard wired washer fluid level switch input to
the cluster. The washer fluid indicator Light Emit-
ting 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 indicator 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
washer fluid indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the indicator is illuminated
for about two seconds as a bulb test.
²Washer Fluid Level Switch Input- Immedi-
ately after the bulb test, if the cluster senses ground
on the washer fluid switch sense circuit for more
than about thirty seconds, it turns on the washer
fluid indicator. Any time after the bulb test, the clus-
ter must sense ground on the washer fluid switch
sense circuit for more than about sixty seconds before
it turns on the indicator. Once illuminated, the indi-
cator will remain illuminated until the ignition
switch is cycled and the cluster senses an open cir-
cuit on the low washer fluid sense input. This strat-
egy is intended to reduce the effect that fluid
sloshing within the washer reservoir can have on
reliable indicator operation.
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 washer fluid level switch is connected in series
between ground and the washer fluid switch sense
input to the instrument cluster. For more informa-
tion on the washer fluid level switch,(Refer to 8 -
ELECTRICAL/WIPERS/WASHERS/WASHER FLUID
LEVEL SWITCH - OPERATION). For further diag-
nosis of the washer fluid indicator or the instrument
BR/BEINSTRUMENT CLUSTER 8J - 35
WAIT-TO-START INDICATOR (Continued)

OPERATION
The water-in-fuel indicator gives an indication to
the vehicle operator when the water accumulated in
the diesel engine fuel filter/separator filter bowl
requires draining. This indicator is controlled by a
transistor on the instrument cluster circuit board
based upon cluster programming and electronic mes-
sages received by the cluster from the Engine Control
Module (ECM) over the Chrysler Collision Detection
(CCD) data bus. The water-in-fuel 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 indicator will always be off
when the ignition switch is in any position except On
or Start. The LED only illuminates when it is
switched to ground by the instrument cluster transis-
tor. The instrument cluster will turn on the water-in-
fuel indicator for the following reasons:
²Bulb Test- Each time the ignition switch is
turned to the On position the indicator is illuminated
for about two seconds as a bulb test.
²Water-In-Fuel Lamp-On Message- Each time
the cluster receives a water-in-fuel lamp-on messagefrom the ECM, the indicator will be illuminated. The
indicator remains illuminated until the cluster
receives a water-in-fuel lamp-off message from the
ECM 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 ECM continually monitors the water-in-fuel
sensor, then sends the proper messages to the instru-
ment cluster. For further diagnosis of the water-in-
fuel indicator or the instrument cluster circuitry that
controls the indicator, (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND TEST-
ING). For proper diagnosis of the water-in-fuel
sensor, the ECM, the CCD data bus, or the message
inputs to the instrument cluster that control the
water-in-fuel indicator, a DRBIIItscan tool is
required. Refer to the appropriate diagnostic
information.
BR/BEINSTRUMENT CLUSTER 8J - 37
WATER-IN-FUEL INDICATOR (Continued)

MARKER LAMP
REMOVAL..............................22
INSTALLATION...........................23
MULTI-FUNCTION SWITCH
DESCRIPTION...........................23
OPERATION.............................24
DIAGNOSIS AND TESTING.................25
MULTI-FUNCTION SWITCH...............25
REMOVAL..............................27
INSTALLATION...........................28
OUTBOARD IDENTIFICATION LAMP
REMOVAL..............................28
INSTALLATION...........................29
PARK/TURN SIGNAL LAMP
REMOVAL..............................29
INSTALLATION...........................29
PARK/TURN SIGNAL LAMP UNIT
REMOVAL..............................29INSTALLATION...........................29
TAIL LAMP
DESCRIPTION...........................29
OPERATION.............................29
REMOVAL..............................29
INSTALLATION...........................30
TAIL LAMP UNIT
REMOVAL..............................30
INSTALLATION...........................30
TURN SIGNAL CANCEL CAM
DESCRIPTION...........................30
OPERATION.............................31
UNDERHOOD LAMP
REMOVAL..............................31
INSTALLATION...........................32
UNDERHOOD LAMP UNIT
REMOVAL..............................32
INSTALLATION...........................32
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION - TURN SIGNAL & HAZARD
WARNING SYSTEM
A turn signal and hazard warning system is stan-
dard factory-installed safety equipment on this
model. The turn signal and hazard warning system
includes the following major components, which are
described in further detail elsewhere in this service
information:
²Combination Flasher- The electronic combi-
nation flasher is installed in the Junction Block (JB),
which is located behind the fuse access panel on the
left outboard end of the instrument panel.
²Hazard Warning Switch- The hazard warning
switch is integral to the multi-function switch on the
left side of the steering column. The hazard warning
switch button protrudes from a dedicated opening in
the shroud on the top of the steering column, just
below the steering wheel.
²Turn Signal Cancel Cam- The turn signal
cancel cam is integral to the clockspring, which is
located beneath the steering column shrouds at the
top of the steering column, just below the steering
wheel.
²Turn Signal Indicators- The two turn signal
indicators, one right and one left, are integral to the
ElectroMechanical Instrument Cluster (EMIC)
located in the instrument panel.
²Turn Signal Lamps- The front turn signal
lamps are integral to the lower front outboard ends
of the headlamp modules, located just outboard of the
two sides of the radiator grille opening. The rear
turn signal lamps are integral to the taillamp mod-
ules located on either side of the vehicle. For pickup
models the taillamp modules are secured to the rear
of the quarter panels at each side of the tailgate
opening. For cab and chassis models the taillampmodules are secured by a stamped steel bracket on
the outboard side of each frame rail near the rear of
the vehicle.
²Turn Signal Switch- The turn signal switch is
integral to the multi-function switch on the left side
of the steering column. The multi-function switch
control stalk that actuates the turn signal switch
protrudes from a dedicated opening in the steering
column shrouds on the left side of the column, just
below the steering wheel.
Hard wired circuitry connects the turn signal and
hazard warning system components to each other
through the electrical system of the vehicle. These
hard wired circuits are integral to several wire har-
nesses, which are routed throughout the vehicle and
retained by many different methods. These circuits
may be connected to each other, to the vehicle elec-
trical system and to the turn signal and hazard
warning system components through the use of a
combination of soldered splices, splice block connec-
tors and many different types of wire harness termi-
nal connectors and insulators. 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.
OPERATION - TURN SIGNAL & HAZARD
WARNING SYSTEM
The turn signal system operates on battery current
received on a fused ignition switch output (run-acc)
circuit so that the turn signals will only operate with
the ignition switch in the On or Accessory positions.
The hazard warning system operates on non-
switched battery current received on a fused B(+) cir-
cuit so that the hazard warning remains operational
8L - 2 LAMPS/LIGHTING - EXTERIORBR/BE

regardless of the ignition switch position. When the
turn signal (multi-function) switch control stalk is
moved up (right turn) or down (left turn), the turn
signal system is activated. When the turn signal sys-
tem is activated, the circuitry of the turn signal
switch and the combination flasher will cause the
selected (right or left) turn signal indicator, front
park/turn signal lamp, and rear tail/stop/turn signal
lamp to flash on and off. With the hazard warning
(multi-function) switch in the On position, the hazard
warning system is activated. When the hazard warn-
ing system is activated, the circuitry of the hazard
warning switch and the combination flasher will
cause both the right side and the left side turn signal
indicators, front park/turn signal lamps, and rear
tail/stop/turn signal lamps to flash on and off.
Refer to the owner's manual in the vehicle glove
box for more information on the features, use and
operation of the turn signal and hazard warning sys-
tem.
DIAGNOSIS AND TESTING - TURN SIGNAL &
HAZARD WARNING SYSTEM
When diagnosing the turn signal and hazard warn-
ing circuits, remember that high generator output
can burn out bulbs rapidly and repeatedly. If this is a
problem on the vehicle being diagnosed, be certain to
diagnose and repair the charging system as required.
If the problem being diagnosed is related to a failure
of the turn signals to automatically cancel following
completion of a turn, inspect the multi-function
switch for a faulty or damaged cancel actuator and
inspect the turn signal cancel cam on the clockspring
for damaged lobes or improper installation. Refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector 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.
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) Turn the ignition switch to the On position.
Actuate the turn signal switch or the hazard warning
switch. Observe the turn signal indicator lamp(s) in
the instrument cluster. If the flash rate is very high,
check for a turn signal bulb that is not lit or is very
dimly lit. Repair the circuits to that lamp or replace
the faulty bulb, as required. If the turn signal indi-
cator(s) fail to light, go to Step 2.
(2) Turn the ignition switch to the Off position.
Check the fused ignition switch output (run-acc) fuse
(Fuse 10 - 10 ampere) in the Junction Block (JB) and
the fused B(+) fuse (Fuse4-20ampere) in the
Power Distribution Center (PDC). If OK, go to Step
3. If not OK, repair the shorted circuit or component
as required and replace the faulty fuse(s).
(3) Check for battery voltage at the fused B(+) fuse
(Fuse4-20ampere) in the PDC. If OK, go to Step 4.
If not OK, repair the open fused B(+) circuit between
the PDC and the battery as required.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run-acc) fuse (Fuse 10 - 10 ampere) in the
JB. If OK, go to Step 5. If not OK, repair the open
fused ignition switch output (run-acc) circuit between
the JB and the ignition switch as required.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the combination flasher from the JB and
replace it with a known good unit. Reconnect the bat-
tery negative cable. Test the operation of the turn
signal and hazard warning systems. If OK, discard
the faulty combination flasher. If not OK, remove the
test flasher and go to Step 6.
(6) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run-acc) circuit cavity in the JB receptacle
for the combination flasher. If OK, go to Step 7. If
not OK, repair the open fused ignition switch output
(run-acc) circuit between the combination flasher and
the fused ignition switch output (run-acc) fuse (Fuse
10 - 10 ampere) in the JB as required.
(7) Turn the ignition switch to the Off position.
Check for battery voltage at the fused B(+) circuit
cavity of the JB receptacle for the combination
flasher. If OK, go to Step 8. If not OK, repair the
open fused B(+) circuit between the combination
flasher and the fused B(+) fuse (Fuse4-20ampere)
in the PDC as required.
(8) Disconnect and isolate the battery negative
cable. Check for continuity between the ground cir-
cuit cavity of the JB receptacle for the combination
flasher and a good ground. There should be continu-
ity. If OK, go to Step 9. If not OK, repair the open
ground circuit to ground (G201) as required.
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 3
LAMPS/LIGHTING - EXTERIOR (Continued)

COMBINATION FLASHER
DESCRIPTION
The combination flasher is located in the Junction
Block (JB) behind the fuse access panel on the left
outboard end of the instrument panel. The combina-
tion flasher is a smart relay that functions as both
the turn signal system and the hazard warning sys-
tem flasher. The combination flasher contains active
electronic Integrated Circuitry (IC) elements. This
flasher is designed to handle the current flow
requirements of the factory-installed lighting. If sup-
plemental lighting is added to the turn signal lamp
circuits, such as when towing a trailer with lights,
the combination flasher will automatically try to
compensate to keep the flash rate the same.
The combination flasher has five blade-type termi-
nals that connect it to the vehicle electrical system
through five matching cavities in the receptacle of
the JB. While the combination flasher has a Interna-
tional Standards Organization (ISO)-type relay ter-
minal configuration or footprint, the internal
circuitry is much different. The combination flasher
does not use standard ISO-relay inputs or provide
ISO-relay type outputs or functions. The combination
flasher should never be substituted for an ISO-relay
or replaced with an ISO-relay, or else component and
vehicle damage may occur.
The combination flasher cannot be repaired or
adjusted and, if faulty or damaged, it must be
replaced.
OPERATION
The combination flasher has five blade-type termi-
nals intended for the following inputs and outputs:
fused B(+), fused ignition switch output, ground, turn
signal circuit, and hazard warning circuit. Constant
battery voltage and ground are supplied to the
flasher so that it can perform the hazard warning
function, and ignition switched battery voltage is
supplied for the turn signal function.
The Integrated Circuitry (IC) within the combina-
tion flasher (Fig. 6) contains the logic that controls
the flasher operation and the flash rate. Pin 6 of the
IC receives a sense voltage from the hazard warning
circuit of the multi-function switch. When the hazard
warning switch is turned on, the9hazard on sense9
voltage will become low due to the circuit being
grounded through the turn signal bulbs. This low
voltage sense signals the IC to energize the flash con-
trol Positive-Negative-Positive (PNP) transistor at a
pre-calibrated flash rate or frequency. Each time the
PNP transistor energizes the hazard warning circuit,
the pin 69hazard on sense9voltage will become high
and the IC signals the PNP transistor to de-energize
the circuit. This cycling will continue until the haz-
ard warning switch is turned off.
Likewise, pin 8 of the IC receives a sense voltage
from the turn signal circuits of the multi-function
switch. When the left or right turn signal switch is
turned on, the9turn signal on sense9voltage will
become low due to the circuit being grounded
through the turn signal bulbs. This low voltage sense
signals the IC to energize the flash control PNP tran-
sistor at a pre-calibrated flash rate or frequency.
Each time the PNP transistor energizes the turn sig-
nal circuit, the pin 89turn signal on sense9voltage
Fig. 5 Roof Clearance Lamps
1 - ROOF
2 - LAMP LENS
3 - BULB
4 - SOCKET
Fig. 6 Combination Flasher - Typical
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 7
CLEARANCE LAMP (Continued)

DAYTIME RUNNING LAMP
MODULE
DESCRIPTION
The Daytime Running Lights (Headlamps) System
is installed on vehicles manufactured for sale in Can-
ada only. A separate module, mounted on the cowl,
controls the DRL.
OPERATION
The headlamps are illuminated when the ignition
switch is turned to the ON position. The DRL module
receives a vehicle-moving signal from the vehicle
speed sensor. This provides a constanthead-
lamps-oncondition as long as the vehicle is moving.
The lamps are illuminated at less than 50 percent of
normal intensity.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Disengage wire connector from DRLM (Fig. 8).
(3) Remove screws attaching DRLM to left front
inner fender panel.
(4) Separate DRLM from fender.
INSTALLATION
(1) Position DRLM on fender.(2) Install screws attaching DRLM to left front
inner fender panel.
(3) Engage wire connector to DRLM.
(4) Connect the battery negative cable.
FOG LAMP
DIAGNOSIS AND TESTING - FOG LAMP
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING OR
IGNITION TURNED OFF.1. Loose or corroded battery cables. 1. Clean and secure battery cable clamps
and posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system.
4. Battery has insufficient charge. 4. Test battery state-of -charge.
5. Battery is sulfated or shorted. 5. Load test battery.
6. Poor lighting circuit Z33-ground. 6. Test for voltage drop across Z33-ground
locations.
FOG LAMP BULBS BURN
OUT FREQUENTLY1. Charging system output too high. 1. Test and repair charging system.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and
splices.
Fig. 8 Daytime Running Lamp Module (DRLM)
1 - HEADLAMP AND DASH WIRING HARNESS
2 - LEFT FENDER SIDE SHIELD
3 - DAYTIME RUNNING LAMP MODULE
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 9

CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS ARE DIM
WITH ENGINE IDLING1. Loose or corroded battery cables. 1. Clean and secure battery cable clamps
and posts.
OR IGNITION TURNED
OFF2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system.
4. Battery has insufficient charge. 4. Test battery state-of -charge.
5. Battery is sulfated or shorted. 5. Load test battery.
6. Poor lighting circuit Z3-ground. 6. Test for voltage drop across Z3-ground
locations.
7. Both headlamp bulbs defective. 7. Replace both headlamp bulbs.
HEADLAMP BULBS BURN
OUT1. Charging system output too high. 1. Test and repair charging system.
FREQUENTLY 2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and
splices.
HEADLAMPS ARE DIM
WITH ENGINE RUNNING1. Charging system output too low. 1. Test and repair charging system.
ABOVE IDLE* 2. Poor lighting circuit Z3-ground. 2. Test for voltage drop across Z3-ground
locations.
3. High resistance in headlamp
circuit.3. Test amperage draw of headlamp circuit.
4. Both headlamp bulbs defective. 4. Replace both headlamp bulbs.
HEADLAMPS FLASH
RANDOMLY1. Poor lighting circuit Z3-ground. 1. Test for voltage drop across Z3-ground
locations.
2. High resistance in headlamp
circuit.2. Test amperage draw of headlamp circuit.
Should not exceed 30 amps.
3. Faulty headlamps switch circuit
breaker.3. Replace headlamp switch.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors and
splices.
HEADLAMPS (HIGH &
LOW) DO NOT
ILLUMINATE1. No voltage at either headlamp. 1. Voltage should always be present. Trace
short circuit and replace BOTH headlamp
fuses. Check wiring circuit from Right
headlamp fuse to headlamp. (Repeat for
Left side)
2. No ground for high and low beam
circuit.2. Ground should always be present
according to switch position. Check ground
at headlamp switch. Check wiring circuit
from headlamp switch to Multifunction
switch. Check headlamp switch and
Multifunction switch continuity. Repair circuit
ground.
3. Headlamp bulb(s) defective. 3. Replace bulb(s).
4. Faulty headlamp switch. 4. Replace headlamp switch.
5. Faulty headlamp dimmer
(Multifunction) switch.5. Replace Multifunction switch.
8L - 14 LAMPS/LIGHTING - EXTERIORBR/BE
HEADLAMP (Continued)

(1) Disconnect and isolate the battery negative
cable. Remove the headlamp switch from the instru-
ment panel. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/HEADLAMP SWITCH -
REMOVAL) for the procedures. Unplug the headlamp
switch wire harness connectors. Check for continuity
between the left door jamb switch sense circuit cavity
of the headlamp switch wire harness connector and a
good ground. There should be continuity with the
driver door open, and no continuity with the driver
door closed. If OK, go to Step 2. If not OK, repair the
circuit to the driver door jamb switch as required.
(2) Remove the Central Timer Module (CTM) from
its mounting bracket to access the CTM wire harness
connectors. (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/BODY CONTROL/
CENTRAL TIMER MODUL - REMOVAL) for the
procedures. Unplug the 14-way CTM wire harness
connector. Remove the key from the ignition lock cyl-
inder. Check for continuity between the key-in igni-
tion switch sense circuit cavity of the 14-way CTM
wire harness connector and a good ground. There
should be no continuity. If OK, go to Step 3. If not
OK, repair the short circuit as required.
(3) Check for continuity between the key-in igni-
tion switch sense circuit cavities of the 14-way CTM
wire harness connector and the headlamp switch
wire harness connector. There should be continuity. If
OK, go to Step 4. If not OK, repair the open circuit
as required.
(4) Check for continuity between the left front door
jamb switch sense circuit terminal and the key-in
ignition switch sense circuit terminal of the head-
lamp switch. There should be no continuity with the
switch in the Off position, and continuity with the
switch in the park or head lamps On position. If
OK,(Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/BODY CONTROL/CENTRAL
TIMER MODUL - DIAGNOSIS AND TESTING) If
not OK, replace the faulty headlamp switch.
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.
(2) Remove the cluster bezel from the instrument
panel. (Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - REMOVAL).
(3) Remove the three screws that secure the head-
lamp switch to the instrument panel (Fig. 17).
(4) Pull the headlamp switch away from the
instrument panel far enough to access the instru-
ment panel wire harness connectors.
(5) Disconnect the two instrument panel wire har-
ness connectors for the headlamp switch from the
connector receptacles on the back of the switch.
(6) Remove the headlamp switch from the instru-
ment panel.
Fig. 17 Headlamp Switch Removal
1 - SCREWS (3)
2 - HEADLAMP SWITCH
3 - INSTRUMENT PANEL WIRE HARNESS CONNECTORS
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 19
HEADLAMP SWITCH (Continued)

includes momentary switching of the headlamp high
beam circuits to provide an optical horn feature
(sometimes referred to as flash-to-pass), which allows
the vehicle operator to momentarily flash the head-
lamp high beams as an optical signalling device.
²Intermittent Wipe Mode- The control knob of
the multi-function switch provides an intermittent
wipe mode with multiple delay interval positions.
²Turn Signal Control- The internal circuitry
and hardware of the multi-function switch provide
both momentary non-detent switching and detent
switching with automatic cancellation for both the
left and right turn signals.
²Washer Mode- A button on the end of the con-
trol stalk of the multi-function switch provides
washer system operation when the button is
depressed towards the steering column.
The multi-function switch cannot be adjusted or
repaired. If any function of the switch is faulty, or if
the switch is damaged, the entire switch unit must
be replaced.
OPERATION
The multi-function switch uses conventionally
switched outputs and a variable resistor to control
the many functions and features it provides using
hard wired circuitry. The switch is grounded at all
times through a single wire take out with an eyelet
terminal connector of the instrument panel wire har-
ness that is secured by a nut to a ground stud
located on the instrument panel armature, just above
and to the left of the glove box opening. When the
ignition switch is in the Accessory or On positions,
battery current from a fuse in the Junction Block
(JB) is provided through a fused ignition switch out-
put (run-acc) circuit. Following are descriptions of
the how the multi-function switch operates to control
the many functions and features it provides:
²Continuous Wipe Modes- When the control
knob of the multi-function switch is rotated to the
High or Low positions, the circuitry within the
switch provides a battery current output directly to
the high or low speed brush of the wiper motor.
When the control knob is in the Off position, the cir-
cuitry within the switch connects the output of the
wiper motor park switch to the low speed brush of
the wiper motor.
²Hazard Warning Control- The hazard warn-
ing push button is pushed down to unlatch the
switch and activate the hazard warning system, and
pushed down again to latch the switch and turn the
system off. When the hazard warning switch is
latched (hazard warning off), the push button will be
in a lowered position on the top of the steering col-
umn shroud; and, when the hazard warning switch is
unlatched (hazard warning on), the push button willbe in a raised position. The multi-function switch
hazard warning circuitry simultaneously provides a
signal to the hazard warning sense of the combina-
tion flasher to activate or deactivate the flasher out-
put, and directs the output of the flasher to the
hazard warning lamps.
²Headlamp Beam Selection- The multi-func-
tion switch control stalk is pulled towards the steer-
ing wheel past a detent, then released to actuate the
headlamp beam selection switch. Each time the con-
trol stalk is actuated in this manner, the opposite
headlamp mode from what is currently selected will
be activated. The internal circuitry of the headlamp
beam selection switch directs the output of the head-
lamp switch through hard wired circuitry to activate
the selected headlamp beam.
²Headlamp Optical Horn- The left multi-func-
tion switch control stalk is pulled towards the steer-
ing wheel to just before a detent, to momentarily
activate the headlamp high beams. The high beams
will remain illuminated until the control stalk is
released. The internal circuitry of the headlamp
beam selection switch provides a momentary ground
path to the headlamp high beams.
²Intermittent Wipe Mode- When the multi-
function switch control knob is rotated to the Delay
position, the circuitry within the switch connects the
output of the wiper motor relay to the low speed
brush of the wiper motor and provides a battery cur-
rent signal to the Central Timer Module (CTM). If
the Delay mode is selected, the control knob can then
be rotated to multiple minor detent positions, which
actuates a variable resistor within the switch and
provides a hard wired output to the CTM that sig-
nals the desired delay interval for the intermittent
wiper feature.
²Turn Signal Control- The multi-function
switch control stalk actuates the turn signal switch.
When the control stalk is moved in the upward direc-
tion, the right turn signal circuitry is activated; and,
when the control stalk is moved in the downward
direction, the left turn signal circuitry is activated.
The multi-function switch turn signal circuitry simul-
taneously provides a signal to the turn signal sense
of the combination flasher to activate or deactivate
the flasher output, and directs the output of the
flasher to the proper turn signal lamps. The turn sig-
nal switch has a detent position in each direction
that provides turn signals with automatic cancella-
tion, and an intermediate, momentary position in
each direction that provides turn signals only until
the left multi-function switch control stalk is
released. When the control stalk is moved to a turn
signal switch detent position, the cancel actuator
extends toward the center of the steering column. A
turn signal cancel cam that is integral to the clock-
8L - 24 LAMPS/LIGHTING - EXTERIORBR/BE
MULTI-FUNCTION SWITCH (Continued)