For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Fog Lights Schematics
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Lighting Systems
2 |

1. Turn ON the ignition, with the engine OFF.
2. Place the headlamp switch in the HEADLAMP position.
3. Place the fog lamp switch in the OFF position.

Do the fog lamps illuminate?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3 | Place the headlamp switch in the OFF position. Do the fog lamps remain illuminated? | Go to Step 4 | Go to Step 6
4 | Remove the fog lamps relay. Do the fog lamps remain illuminated? | Go to Step 10 | Go to Step 5
5 | Probe the fog lamp relay control circuit of the fog lamps relay with a test lamp that is connected to battery positive voltage. Does the test lamp illuminate? | Go to Step 7 | Go to Step 11
6 | Test the front fog lamp switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 8
7 | Test the fog lamp relay control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 9
8 | Inspect for poor connections at the harness connector of the fog lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 12
9 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13
10 | Repair a short to voltage in the front fog lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair | Go to Step 14 | --
11 | Replace the fog lamps relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 14 | --
12 | Replace the fog lamp switch. Refer to Fog Lamp Switch Replacement . Did you complete the replacement? | Go to Step 14 | --
13 | Important: Perform the set up procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control Systems. Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 14 | --
14 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3