2002 DODGE RAM battery

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 behind
the 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
cluster circuitry that controls the indicator, (Refer to
8 - ELECTRICAL/INSTRUMENT CLUSTER - DIAG-
NOSIS AND TESTING). The washer fluid level
switch input to the cluster can be diagnosed using
conventional diagnostic tools and methods.
DIAGNOSIS AND TESTING - WASHER FLUID
INDICATOR
The diagnosis found here addresses an inoperative
washer fluid indicator condition. If the problem being
diagnosed is related to indicator accuracy, be certain
to confirm that the problem is with the indicator or
washer fluid level switch input and not with a dam-
aged or empty washer fluid reservoir, or inoperative
instrument cluster indicator control circuitry. Inspect
the washer fluid reservoir for proper fluid level and
signs of damage or distortion that could affect
washer fluid level switch performance and perform
the instrument cluster actuator test before you pro-
ceed with the following diagnosis. If no washer fluid
reservoir or instrument cluster control circuitry prob-
lem is found, the following procedure will help to
locate a short or open in the washer fluid switch
sense circuit. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, 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.
BR/BEINSTRUMENT CLUSTER 8J - 35

INDICATOR DOES NOT ILLUMINATE WITH WASHER
RESERVOIR EMPTY
(1) Disconnect and isolate the battery negative
cable. Disconnect the headlamp and dash wire har-
ness connector for the washer fluid level switch from
the washer fluid level switch connector receptacle.
Check for continuity between the ground circuit cav-
ity of the headlamp and dash wire harness connector
for the washer fluid level switch and a good ground.
There should be continuity. If OK, go to Step 2. If not
OK, repair the open ground circuit to ground (G100)
as required.
(2) Remove the instrument cluster from the instru-
ment panel. Check for continuity between the washer
fluid switch sense circuit cavities of the headlamp
and dash wire harness connector for the washer fluid
level switch and the instrument panel wire harness
connector (Connector C2) for the instrument cluster.
If OK, replace the faulty washer fluid level switch. If
not OK, repair the open washer fluid switch sense
circuit between the washer fluid level switch and the
instrument cluster as required.
INDICATOR STAYS ILLUMINATED WITH WASHER
RESERVOIR FULL
(1) Disconnect and isolate the battery negative
cable. Disconnect the headlamp and dash wire har-
ness connector for the washer fluid level switch from
the washer fluid level switch connector receptacle.
Check for continuity between the ground circuit ter-
minal and the washer fluid switch sense terminal in
the washer fluid level switch connector receptacle.
There should be no continuity. If OK, go to Step 2. If
not OK, replace the faulty washer fluid level switch.
(2) Remove the instrument cluster from the instru-
ment panel. Check for continuity between the washer
fluid switch sense circuit cavity of the headlamp and
dash wire harness connector for the washer fluid
level switch and a good ground. There should be no
continuity. If not OK, repair the shorted washer fluid
switch sense circuit between the washer fluid level
switch and the instrument cluster as required.
WATER-IN-FUEL INDICATOR
DESCRIPTION
A water-in-fuel indicator is standard equipment on
all instrument clusters, but is only functional in vehi-
cles equipped with an optional diesel engine. The
water-in-fuel indicator is located near the lower edge
of the instrument cluster overlay, to the left of center.
The water-in-fuel indicator consists of a stencilled
cutout of the text ªWATER IN FUELº 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 redlens located behind the cutout causes the ªWATER
IN FUELº text to appear in red through the translu-
cent outer layer of the overlay when the indicator is
illuminated from behind by a Light Emitting Diode
(LED) soldered onto the instrument cluster electronic
circuit board. The water-in-fuel indicator is serviced
as a unit with the instrument cluster.
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 message
from 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.
8J - 36 INSTRUMENT CLUSTERBR/BE
WASHER FLUID INDICATOR (Continued)

INSTALLATION.........................22
MARKER LAMP
REMOVAL.............................23
INSTALLATION.........................23
MULTI-FUNCTION SWITCH
DESCRIPTION.........................23
OPERATION...........................24
DIAGNOSIS AND TESTING - 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.........................31
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 tailgateopening. For cab and chassis models the taillamp
modules 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-
8L - 2 LAMPS/LIGHTING - EXTERIORBR/BE

switched battery current received on a fused B(+) cir-
cuit so that the hazard warning remains operational
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)

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, current is
routed to the speed control servo solenoids. The
speed control solenoids (vacuum, vent and dump) are
provided this current any time the speed control is
ON and the brakes are disengaged.
When the driver applies the brakes, the contacts
open and current 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.
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. 1).
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) Remove knee bolster for access to brake lamp
switch and pedal.
(2) Disconnect switch harness (Fig. 2) .
(3) Press and hold brake pedal in applied position.
(4) Rotate switch counterclockwise about 30É to
align switch lock tabs with notch in bracket.
(5) Pull switch rearward out of mounting bracket
and release brake pedal.
Fig. 1 Brake Lamp Switch Terminal Identification
1 - TERMINAL PINS
2 - PLUNGER TEST POSITIONS
Fig. 2 Brake Lamp Switch & Harness Connector
1 - BRAKE LIGHT SWITCH
2 - SWITCH BRACKET
3 - HARNESS CONNECTOR
4 - SWITCH LEVER
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 5
BRAKE LAMP SWITCH (Continued)

INSTALLATION
(1) Connect harness wires tonewswitch.
(2) Press and hold brake pedal down.
(3) Align tabs on switch with notches in switch
bracket, install the switch and rotate it in bracket
clockwise approximately 30É to lock it in place. (Fig.
3). Make sure the switch lever is in the 45É position
as illistrated in figure 2.
(4) Release brake pedal. With out moving the
pedal, move the lever so that it is parallel with the
connector. The switch is now adjusted and can not be
adjusted again.
(5) Install the knee bolster.
CENTER HIGH MOUNTED
STOP LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the CHMSL from the roof panel.
(3) Rotate sockets 1/4 turn clockwise and remove
from lamp. (The two center bulbs light the stoplamp
and the outside bulbs light the cargo lamp, if
equipped.)
(4) Pull bulb from socket.
INSTALLATION
(1) Push bulb into socket.
(2) Position socket in lamp an rotate socket 1/4
turn counterclockwise.
(3) Install the CHMSL.
(4) Connect the battery negative cable.
CENTER HIGH MOUNTED
STOP LAMP UNIT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove screws holding CHMSL to roof panel
(Fig. 4).
(3) Separate CHMSL from roof.
(4) Disengage wire connector from body wire har-
ness.
(5) Separate CHMSL from vehicle.
INSTALLATION
(1) Position lamp at cab roof and connect wire con-
nector.
(2) Install screws holding CHMSL to roof panel.
Tighten securely.
(3) Connect the battery negative cable.
Fig. 3 Brake Lamp Switch
1 - TAB NOTCH (IN BRACKET)
2 - SWITCH PLUNGER
3 - SWITCH TAB
Fig. 4 Center High Mounted Stop Lamp
1 - CHMSL CARGO LAMP HOUSING
2 - CHMSL
3 - CARGO LAMPS
4 - SCREW
5 - CLIP
6 - CAB
8L - 6 LAMPS/LIGHTING - EXTERIORBR/BE
BRAKE LAMP SWITCH (Continued)

CLEARANCE LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove screws holding clearance lamp lens to
roof panel (Fig. 5).
(3) Rotate socket 1/4 turn counterclockwise and
separate socket from lamp.
INSTALLATION
(1) Install socket in lamp and rotate socket 1/4
turn clockwise.
(2) Position clearance lamp on roof.
(3) Install screws holding clearance lamp lens to
roof panel. Tighten to 1 N´m (13 in. lbs.).
(4) Connect the battery negative cable.
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.
Fig. 5 Roof Clearance Lamps
1 - ROOF
2 - LAMP LENS
3 - BULB
4 - SOCKET
5 - PLASTIC NUTS
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 7

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
will become high and the IC signals the PNP transis-
tor to de-energize the circuit. This cycling will con-
tinue until the right or left turn signal switch is
turned off.A special design feature of the combination flasher
allows it to9sense9that a turn signal circuit or bulb
is not operating, and provide the driver an indication
of the condition by flashing the remaining bulbs in
the affected circuit at a higher rate (120 flashes-per-
minute or higher). Conventional flashers either con-
tinue flashing at their typical rate (heavy-duty type),
or discontinue flashing the affected circuit entirely
(standard-duty type). During turn signal operation,
the combination flasher IC compares normal battery
voltage input on pin 2 with the shunt resistor voltage
input on pin 7. If the IC9senses9that the voltage dif-
ference between pin 2 and pin 7 is different than the
pre-calibrated value of the IC, it will increase the
rate at which it signals the PNP transistor to ener-
gize the pin 1 output. Thus, the inoperative half (left
or right side) of the turn signal circuit will flash
faster.
Because of the active electronic elements within
the combination flasher, it cannot be tested with con-
ventional automotive electrical test equipment. If the
combination flasher is believed to be faulty, test the
turn signal system and hazard warning system. Then
replace the combination flasher with a known good
unit to confirm system operation. (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/TURN
SIGNAL & HAZARD WARNING SYSTEM - DIAG-
NOSIS AND TESTING).
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 fuse access panel by unsnapping it
from the left outboard end of the instrument panel.
(3) Remove the combination flasher from the Junc-
tion Block (JB) (Fig. 7).
Fig. 6 Combination Flasher - Typical
8L - 8 LAMPS/LIGHTING - EXTERIORBR/BE
COMBINATION FLASHER (Continued)