GM Service Manual Online
For 1990-2009 cars only

Fog Lamps Inoperative Export, Rear

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

1

Did you review the fog lamp operation and perform the necessary inspections?

Go to Step 2

Go to Exterior Lighting Systems Description and Operation

2

  1. Turn ON the headlamps.
  2. Turn ON the rear fog lamp.

Does the system operate normally?

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

Go to Step 3

3

Is only the rear fog lamp indicator inoperative?

Go to Step 4

Go to Step 5

4

Test the headlamp switch signal circuit of the rear fog lamp switch for high resistance or an open.

Did you find and correct the condition?

Go to Step 20

Go to Step 15

5

Is the rear fog lamp switch illumination operative?

Go to Step 7

Go to Step 6

6

Test the ground circuit of the rear fog lamp switch for high resistance or an open.

Did you find and correct the condition?

Go to Step 20

Go to Step 7

7

  1. Remove the rear fog lamp relay.
  2. Connect a fused jumper between the battery positive voltage circuit and the rear fog lamp supply voltage circuit of the rear fog lamp relay connector.

Does the rear fog lamp illuminate?

Go to Step 10

Go to Step 8

8

Test the battery positive voltage circuit of the rear fog lamp relay for high resistance or an open.

Did you find and correct the condition?

Go to Step 20

Go to Step 9

9

Test the rear fog lamp supply circuits between the rear fog lamp relay and ground for a high resistance or an open.

Did you find and correct the condition?

Go to Step 20

Go to Step 13

10

Connect a test lamp between the headlamp switch signal circuit of the rear fog lamp relay and a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 16

11

Connect a test lamp between the rear fog lamp relay control circuit of the rear fog lamp relay and a battery positive voltage circuit.

Does the test lamp illuminate?

Go to Step 14

Go to Step 12

12

Test the rear fog lamp relay control circuit of the rear fog lamp relay for a high resistance or an open.

Did you find and correct the condition?

Go to Step 20

Go to Step 15

13

Inspect for poor connections at the harness connector of the rear fog lamp bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 17

14

Inspect for poor connections at the harness connector of the rear fog lamp relay. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 18

15

Inspect for poor connections at the harness connector of the rear fog lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 19

16

Repair the headlamp switch signal circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

--

17

Replace the rear fog lamp bulb. Refer to Rear Fog Lamp Bulb Replacement

Did you complete the replacement?

Go to Step 20

--

18

Replace the rear fog lamp relay.

Did you complete the replacement?

Go to Step 20

--

19

Replace the rear fog lamp bulb. Refer to Rear Fog Lamp Switch Replacement

Did you complete the replacement?

Go to Step 20

--

20

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

Fog Lamps Inoperative Luxury

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

1

Did you review the fog lamps operation and perform the necessary inspections?

Go to Step 2

Go to Exterior Lighting Systems Description and Operation

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the low beam headlamps.
  3. Turn ON the fog lamps.

Does the fog lamp system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

Do the low beam headlamps operate correctly?

Go to Step 4

Go to Headlamps Inoperative - Low Beams

4

Is only one lamp inoperative?

Go to Step 7

Go to Step 5

5

Is the fog lamp ON indicator inoperative while the fog lamps are illuminated?

Go to Step 9

Go to Step 6

6

Is the fog lamp ON indicator illuminated while the fog lamps are inoperative.

Go to Step 11

Go to Step 15

7

Test the front fog lamps supply voltage circuit of the inoperative lamp for high resistance or an open.

Did you find and correct the condition?

Go to Step 36

Go to Step 18

8

Test the ground circuit of the inoperative lamp for high resistance or an open.

Did you find and correct the condition?

Go to Step 36

Go to Step 23

9

Test the ground circuit of the fog lamp switch for a high resistance, or an open.

Did you find and correct the condition?

Go to Step 36

Go to Step 10

10

Test the front fog lamp switch signal circuit of the fog lamp switch for high resistance or an open.

Did you find and correct the condition?

Go to Step 36

Go to Step 25

11

  1. Turn OFF the ignition.
  2. Remove the fog lamp relay.
  3. Connect a fused jumper wire between the front fog lamps supply voltage circuit of the fog lamp relay and battery positive voltage.

Do the fog lamps illuminate?

Go to Step 36

Go to Step 28

12

Test the battery positive voltage circuit of the fog lamp relay for high resistance, an open, or a short to ground.

Did you find and correct the condition?

Go to Step 36

Go to Step 13

13

Test the front fog lamp switch signal circuit of the fog lamp relay for high resistance, or an open.

Did you find and correct the condition?

Go to Step 36

Go to Step 14

14

Test the ground circuit of the fog lamp relay for high resistance, or an open.

Did you find and correct the condition?

Go to Step 36

Go to Step 24

15

  1. Turn OFF the ignition.
  2. Disconnect the fog lamp switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a fused jumper wire between the front fog lamp switch signal circuit and the front fog lamp switch supply voltage circuit of the fog lamp switch.

Do the fog lamps illuminate?

Go to Step 25

Go to Step 16

16

  1. Turn OFF the ignition.
  2. Remove the jumper wire.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a fused jumper wire between the front fog lamp switch signal circuit of the fog lamp switch and battery positive voltage.

Do the fog lamps illuminate?

Go to Step 17

Go to Step 29

17

  1. Turn OFF the ignition.
  2. Remove the jumper wire.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect test lamp between the front fog lamp switch supply voltage circuit of the fog lamp switch and ground.

Does the test lamp illuminate?

Go to Step 25

Go to Step 18

18

  1. Turn OFF the ignition.
  2. Remove enable relay
  3. Turn ON the ignition, with the engine OFF.
  4. Connect test lamp between the DRL relay control circuit of the fog lamp enable relay and battery positive voltage.

Does the test lamp illuminate?

Go to Step 19

Go to Step 20

19

Test the DRL control relay circuit for a short to ground.

Did you find and correct the condition?

Go to Step 36

Go to Step 22

20

Test the headlamp low beam supply voltage circuit for a high resistance, or and open.

Did you find and correct the condition?

Go to Step 36

Go to Step 21

21

Test the front fog lamp supply voltage circuit of the enable relay for high resistance, an open, or a short to ground.

Did you find and correct the condition?

Go to Step 36

Go to Step 26

22

Connect test lamp between the ignition 1 voltage circuit of the enable relay and ground.

Does the test lamp illuminate?

Go to Step 27

Go to Step 30

23

Inspect for poor connections at the harness connector of the inoperative lamp and bulb. 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 36

Go to Step 31

24

Inspect for poor connections at the harness connector of the fog lamp relay. 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 36

Go to Step 32

25

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 36

Go to Step 33

26

Inspect for poor connections at the harness connector of the fog lamp enable relay. 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 36

Go to Step 34

27

Inspect for poor connections at the harness connector of the DRL control module. 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 36

Go to Step 35

28

Repair the front fog lamps supply voltage circuit.

Did you complete the repair?

Go to Step 36

--

29

Repair the front fog lamp switch signal circuit between S261 and the fog lamp switch.

Did you complete the repair?

Go to Step 36

--

30

Repair the ignition 1 voltage circuit between S261 and the DRL control module.

Did you complete the repair?

Go to Step 36

--

31

Replace the inoperative lamp or bulb. Refer to Front Fog Lamp Replacement or Front Fog Lamp Bulb Replacement .

Did you complete the replacement?

Go to Step 36

--

32

Replace the fog lamp relay. Refer to Fog Lamp Relay Replacement .

Did you complete the replacement?

Go to Step 36

--

33

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

Did you complete the replacement?

Go to Step 36

--

34

Replace the fog lamp enable relay.

Did you complete the replacement?

Go to Step 36

--

35

Replace the DRL control module. Refer to Daytime Running Lights (DRL) Control Module Replacement .

Did you complete the replacement?

Go to Step 36

--

36

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3