Cluster Illumination Lamps; Four-Wheel Drive Indicator Lamp - Dodge ram truck 3500 1996 Service Manual

8E - 1 2 INSTRUMENT PANEL SYSTEMS
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PI A6NGSIS AMD TESTING (Continued!
Group 19 - Steering to check the steering column
ground clip Installation.
(5) Disconnect and isolate the battery negative
cable. Unplug the ignition switch connector. While
holding the ignition switch in the Start position,
check for continuity between the red brake warning
lamp driver circuit terminal of the ignition switch
and a good ground. There should be continuity.
Release the ignition switch to the On position and
check for continuity again. There should be no conti­
nuity. I f OK, go to Step 6. I f not OK, repair the igni­
tion switch case ground or replace the faulty ignition
switch as required.
(6) Remove the instrument cluster bezel and the
cluster assembly. Connect the battery negative cable
and the ignition switch connector. Do not unplug the
cluster connectors. Install a jumper wire between the
red brake warning lamp driver circuit cavity of the
left cluster connector and a good ground. Turn the
Ignition switch to the On position. The lamp should
light. I f OK, go to Step 7. I f not OK, replace the
faulty bulb.
(7) Turn the ignition switch to the Off position and
remove the jumper wire. Disconnect and isolate the
battery negative cable. Unplug the ignition switch,
parking brake switch, vacuum sensor (diesel engine
only) and brake warning switch connectors. Unplug
the connector at the RWAL or ABS control module, as
equipped. Unplug the left cluster connector. Check
for continuity between the red brake warning lamp
driver circuit cavity of the left cluster connector and
a good ground. There should be no continuity. I f OK,
go to Step 8. I f not OK, repair the short circuit as
required.
(8) Check for continuity between the red brake
warning lamp driver circuit cavities of the left cluster
connector and the following connectors:,
• Parking brake switch
• Brake warning switch
• Vacuum sensor (diesel engine'only)
• Ignition switch
• RWAL control module
• ABS control module.
(9) I n each case there should be continuity. I f not
OK, repair the open circuit as required.
CLUSTER ILLUMINATION LAMPS
For circuit descriptions and diagrams, refer to
8W-40 - instrument Cluster in Group 8W - Wiring
Diagrams.
(1) Check the fuse in the fuseblock module. I f OK,
go to Step 2. i f not OK, replace the faulty fuse.
(2) Turn the park lamps on with the headlamp
switch. Rotate the headlamp switch knob counter­
clockwise to just before the interior lamps detent.
Check for battery voltage at the fuse in the fuseblock
module. Rotate the headlamp switch knob clockwise
while observing the test voltmeter. The reading
should go from battery voltage to zero volts. I f OK,
go to Step 3. I f not OK, repair the open circuit to the
headlamp switch or refer to Group 8L, - Lamps to
diagnose the headlamp switch.
(3) . Disconnect and Isolate the battery negative
cable. Remove the instrument cluster bezel and the
cluster assembly. Unplug the right cluster connector.
Connect the battery negative cable. Turn. the park
lamps on with the headlamp switch. Rotate the head­
lamp switch knob counterclockwise to just before the
interior lamps detent. Check for battery voltage at
the fused panel lamps dimmer switch signal circuit
cavity of the right cluster connector. I f OK, go to Step
4. I f not OK, repair the open circuit as required.
(4) Turn the park lamps off. Disconnect and Isolate
the battery negative cable. Remove the fuse from the
fuseblock module. Probe the fused panel lamps dim­
mer switch signal circuit cavity of the right cluster
connector. Check for continuity to a good ground.
There should be no continuity. I f OK, go to Step 5. I f
not OK, repair the short circuit as required.
(5) Check for continuity between the fused panel
lamps dimmer switch signal circuit cavity of the
right cluster connector and the output side of the
fuse cavity. There should be continuity. I f OK, replace
the faulty bulb(s). I f not OK, repair the open circuit
as required.
FOUR-WHEEL DRIVE INDICATOR LAMP
The diagnosis found here addresses an inoperative
four-wheel drive indicator lamp condition. I f the
problem being diagnosed is related to lamp accuracy,
be certain to confirm that the problem is with the
lamp or switch and not with a damaged or inopera­
tive front axle disconnect. Refer to Group 2 - Front
Suspension and Axle for more information. I f no front
axle disconnect problem is found, the following proce­
dure will help locate a short or open i n the indicator
lamp circuit. For circuit diagrams and descriptions,
refer to 8W-40 - Instrument Cluster i n Group 8W -
Wiring Diagrams.
(1) Turn the ignition switch to the On position.
Unplug the four-wheel drive switch connector at the
front axle disconnect housing. Install a jumper wire
between the two cavities in the switch connector. The
lamp should light. Remove the jumper and the lamp
should go off. I f OK, replace the faulty four-wheel
drive switch. I f not OK, go to Step 2.
(2) Turn the ignition switch to the Off position.
Check for continuity between the ground circuit cav­
ity of the four-wheel drive switch connector and a
good ground. There should be continuity. I f OK, go to
Step 3. I f not OK, repair the ground circuit as
required.