GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

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

Are the fog lamps off?

Go to Step 3

Go to Step 4

3

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

Are the fog lamps off?

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

Go to Step 9

4

Remove the fog lamp relay.

Do the fog lamps turn off?

Go to Step 5

Go to Step 7

5

Connect a test lamp between the coil side supply of the fog lamp relay and the control circuit of the fog lamp relay.

Does the test lamp illuminate?

Go to Step 6

Go to Step 11

6

  1. Leave the test lamp connected.
  2. Disconnect the fog lamp switch.

Is the test lamp illuminated?

Go to Step 8

Go to Step 10

7

Test for a short to battery positive voltage in the fog lamp supply voltage circuit and the fog lamp indicator supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

8

Repair a short to ground in the control circuit of the fog lamp relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Has the repair been made?

Go to Step 13

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9

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

Has the repair been made?

Go to Step 13

--

10

Replace the fog lamp switch. Refer to Fog Lamp Switch Replacement .

Has the repair been made?

Go to Step 13

--

11

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

Has the repair been made?

Go to Step 13

--

12

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

Has the repair been made?

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