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 in Wiring Systems

1

Did you perform the Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn the ignition to the ON position.
  2. Press the fog lamp switch to the OFF position.

Are the fog lamps off?

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

Go to Step 3

3

Remove the fog lamp relay.

Do the fog lamps turn OFF?

Go to Step 5

Go to Step 4

4

  1. Reinstall the fog lamp relay.
  2. Test for a short to battery positive voltage on the fog lamp switched battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

5

Using a test lamp connected to ground, probe the fog lamp coil voltage supply circuit.

Does the test lamp illuminate?

Go to Step 6

Go to Step 9

6

  1. Disconnect the BCM connector C1.
  2. Reinstall the fog lamp relay.

Do the fog lamps remain ON?

Go to Step 10

Go to Step 7

7

  1. Disconnect the BCM connector C2.
  2. Reconnect the BCM connector C1.

Are the fog lamps illuminate?

Go to Step 11

Go to Step 8

8

Test the fog lamp switch signal for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

9

Replace the fog lamp relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

10

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

Did you complete the repair?

Go to Step 14

--

11

Important: Perform the setup procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Computer/Integrating Systems.

Replace the BCM. Refer to Body Control Module Replacement in Computer/Integrating Systems.

Did you complete the replacement?

Go to Step 14

--

12

Replace the multifunction switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 14

--

13

Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

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 2