Grand Cherokee 2WD V8-4.7L VIN J (2004)
Headlamp Switch: Testing and Inspection
Headlamp Switch Test
Before testing the headlamp switch, turn on the exterior lighting and open the driver side front door. If the exterior lamps of the vehicle operate, but there
is no chime warning issued with the driver side front door open. If the exterior lamps of the vehicle are inoperative, but the chime warning is issued.
If the exterior lamps and the chime warning are both inoperative, test the left multi-function switch. If the multi-function switch tests OK, proceed as
follows. The following tests will help to locate a short or open in the hard wired circuits between the multi-function switch and the Body Control Module
(BCM). For complete circuit diagrams, refer to the appropriate wiring information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, REFER TO ELECTRICAL, RESTRAINTS BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
1. Disconnect and isolate the battery negative cable. Disconnect the instrument panel wire harness connector from the left multi-function switch
connector. Disconnect the instrument panel wire harness connector from the Body Control Module (BCM). Check for continuity between the
headlamp switch mux circuit of the instrument panel wire harness connector for the multi-function switch and a good ground. There should be no
continuity. If OK, go to Step 2. If not OK, repair the shorted headlamp switch mux circuit.
2. Check for continuity between the headlamp switch mux circuit of the instrument panel wire harness connector for the multi-function switch and the
instrument panel wire harness connector for the BCM. There should be continuity. If OK, go to Step 3. If not OK, repair the open headlamp switch
mux circuit.
3. Check for continuity between the headlamp switch return circuit of the instrument panel wire harness connector for the multi-function switch and a
good ground. There should be no continuity. If OK, go to Step 4. If not OK, repair the shorted headlamp switch return circuit.
4. Check for continuity between the headlamp switch return circuit of the instrument panel wire harness connector for the multi-function switch and
the instrument panel wire harness connector for the BCM. There should be continuity. If OK, use a DRBIII(R)(R) scan tool and the proper
Diagnostic Procedures manual to test the BCM. If not OK, repair the open headlamp switch return circuit.
