Four Wheel Drive Indicator Lamp: Testing and Inspection

Four-Wheel Drive Indicator Lamp

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, REFER TO AIRBAG SYSTEMS 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. Unplug the wire harness connector at the transfer case switch. Check for continuity between the ground circuit cavity of the transfer case switch wire harness connector and a good ground. There should be continuity. If OK, go to Step 2. If not OK, repair the open circuit as required.

Transfer Case Switch Chart:

2. Check the transfer case switch continuity while shifting the transfer case shift lever to the proper positions. The switch continuity should be as shown. If OK, go to Step 3. If not OK, replace the faulty switch.
3. Disconnect and isolate the battery negative cable. Remove the GDM. Unplug the GDM wire harness connector.
4. Check the continuity of the circuit for the indicator lamp or wheel lamp that is not functioning between the GDM wire harness connector and the transfer case switch wire harness connector. There should be continuity. If OK, go to Step 5. If not OK, repair the open circuit as required.
5. Replace the bulb for the inoperative indicator lamp or wheel lamp. Plug in the GDM and transfer case wire harness connectors. Connect the battery negative cable and check the operation of the inoperative lamp. If OK, discard the faulty bulb. If not OK, replace the faulty GDM.