GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

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

Do the fog lamps remain illuminated?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

Disconnect the FOG LP relay.

Did the fog lamps turn OFF?

Go to Step 4

Go to Step 8

4

  1. Reinstall the FOG LP relay.
  2. Disconnect the lamp switch assembly.

Do the fog lamps remain illuminated?

Go to Step 5

Go to Step 10

5

Disconnect the body control module (BCM) connector C3.

Do the fog lamps remain illuminated?

Go to Step 6

Go to Step 9

6

Disconnect the BCM connector C1.

Do the fog lamps remain illuminated?

Go to Step 7

Go to Step 12

7

Test for a short to ground in the fog lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 13

Go to Step 11

8

Repair a short to battery positive voltage in the fog lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 13

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9

Repair a short to ground in the fog lamp switch signal circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 13

--

10

Replace the lamp switch assembly. Refer to Headlamp Switch Replacement .

Did you complete the repair?

Go to Step 13

--

11

Replace the FOG LP relay. Refer to Relay Replacement .

Did you complete the replacement?

Go to Step 13

--

12

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2