GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Cobalt 🢒 Body 🢒 Lighting Systems 🢒 Fog Lamps Inoperative

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

Connector End View Reference: Master Electrical Component List

DEFINITION: Use this chart if either the front or the rear fog lamp is inoperative.

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. Turn the headlamp switch to the PARK position.
  3. Turn the fog lamps to the ON position.

Do both fog lamps illuminate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Using a scan tool, command the fog lamps ON.

Do the fog lamps illuminate?

Go to Step 5

Go to Step 4

4
  1. Disconnect the FOGLP fuse.
  2. Probe the switch side of the fog lps relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 11

5

Using a scan tool, observe the Fog Lamp Switch Data parameter while pressing the fog lamp switch.

Does the scan tool display active when pressing the switch and inactive when you release the switch?

Go to Step 12

Go to Step 6

6
  1. Disconnect the fog lamp switch.
  2. Observe the Fog Lamp Switch Data parameter.

Does the scan tool display inactive?

Go to Step 7

Go to Step 9

7
  1. Connect a 3-amp fused jumper wire between the fog lamp switch signal circuit of the fog lamp switch and a good ground.
  2. Observe the Fog Lamp Switch Data parameter.

Does the scan tool display active?

Go to Step 13

Go to Step 10

8

Test for the following in the fog lamp voltage supply circuit:

    • An open
    • A high resistance
    • A short to ground

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 11

9

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

Did you find and correct the condition?

Go to Step 17

Go to Step 12

10

Test the fog lamp switch signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 12

11

Inspect for poor connections at the harness connector of the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 16

12

Inspect for poor connections at the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 14

13

Inspect for poor connections at the fog lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 17

Go to Step 15

14

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

Did you complete the replacement?

Go to Step 17

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15

Replace the fog lamp switch.

Did you complete the replacement?

Go to Step 17

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16

Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Bracket Replacement .

Did you complete the replacement?

Go to Step 17

--

17

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2