Fog Lamps Inoperative - Rear

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
Schematic Reference: Fog Lights Schematics
1	Did you perform the Lighting Systems Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - Lighting Systems
2	Verify that the rear fog lamp is inoperative. Does the rear fog lamp operate normally?	Go to TESTING FOR INTERMITTENT CONDITIONS AND POOR CONNECTIONS in Wiring Systems	Go to Step 3
3	Inspect the inoperative bulb and socket for an open filament or poor terminal contact and replace or repair as necessary. Did you find and correct a condition?	Go to Step 15	Go to Step 4
4	With the engine Off, turn the key to RUN and the headlamp switch to PARK. Do the park lamps illuminate?	Go to Step 5	Go to Symptoms - Lighting Systems
5	Inspect the RR FOG fuse. Is the fuse open?	Go to Step 6	Go to Step 7
6	Test for a short to ground in the rear fog lamp supply voltage circuit. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct a condition?	Go to Step 15	Go to Step 13
7	Place the rear fog lamp switch in the ON position. Remove the rear fog lamp relay. Test for a ground signal at the rear fog lamp relay control circuit terminal in the body relay block. Refer to CIRCUIT TESTING in Wiring Systems. Was a ground signal present?	Go to Step 10	Go to Step 8
8	Test the rear fog lamp switch signal and ground circuits for an open or high resistance. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct a condition?	Go to Step 15	Go to Step 9
9	Remove the fog lamp switch. Place a fused jumper between the fog lamp switch signal and ground connector terminals. Test for a ground signal at the rear fog lamp relay control circuit terminal in the body relay block. Refer to CIRCUIT TESTING in Wiring Systems. Was a ground signal present?	Go to Step 14	Go to Step 11
10	Test for an open or high resistance in the rear fog lamp supply voltage circuit and the ground circuit. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct a condition?	Go to Step 15	Go to Step 13
11	Inspect for poor connections at the harness connector of the Body Control Module (BCM). Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition?	Go to Step 15	Go to Step 12
12	IMPORTANT: Perform the setup procedure for the BCM. Replace the body control module (BCM). Refer to BODY CONTROL MODULE REPLACEMENT in Body Control System.Did you complete the replacement?	Go to Step 15	-
13	Replace the rear fog lamp relay. Refer to Fog Lamp Relay Replacement (RPO T96) Fog Lamp Relay Replacement (RPO T79) in Wiring Systems. Did you complete the repair?	Go to Step 15	-
14	Replace the rear fog lamp switch. Refer to Headlamp Switch Replacement . Did you complete the repair?	Go to Step 15	-
15	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3