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For 1990-2009 cars only

Fog Lamps Inoperative Front

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn On the ignition, with the engine OFF.
  2. Turn ON the park lamps.
  3. Turn ON the fog lamps.

Do both fog lamps illuminate?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 4

Go to Step 6

4

At the inoperative lamp, test the front fog lamps supply voltage circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 5

5

At the inoperative lamp, test the front fog lamps ground circuit for high resistance or an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 20

6

  1. Turn ON the park lamps.
  2. With the scan tool, observe the Park Lamps Data parameter.

Does the scan tool display ON?

Go to Step 7

Go to Park Lamps Inoperative

7

With the scan tool, command the fog lamps ON.

Do the fog lamps illuminate?

Go to Step 8

Go to Step 11

8

  1. With the scan tool, read the front fog lamp switch status.
  2. While reading the scan tool, press the fog lamp switch and hold the switch.

Does the scan tool display the switch status as ON?

Go to Step 9

Go to Step 14

9

With the scan tool, read the Park Lamps status.

Does the scan tool display the switch status as ON?

Go to Step 18

Go to Step 10

10

  1. Turn OFF the ignition.
  2. Disconnect the BCM connector C2.
  3. Turn the ignition ON, with the engine OFF.
  4. Connect a test lamp between the interior park lamps supply voltage circuit of the BCM and a good ground.

Does the test lamp illuminate?

Go to Step 18

Go to Step 22

11

Test the front fog lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 12

12

  1. Disconnect the fog lamp relay.
  2. Connect a test lamp between the fog lamp relay control circuit of the fog lamp relay and a battery positive voltage circuit.
  3. While probing, press the switch the switch.

Does the test lamp illuminate?

Go to Step 19

Go to Step 13

13

Test for high resistance or an open in the fog lamp relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 27

Go to Step 14

14

  1. Turn OFF the ignition.
  2. Remove the fog lamp switch from instrument panel (IP) without disconnecting the connector.
  3. Connect a test lamp between the switch ground circuit of the fog lamp switch and a battery positive voltage circuit.

Does the test lamp illuminate?

Go to Step 15

Go to Step 21

15

  1. Disconnect the BCM.
  2. Connect a test lamp between the front fog lamp switch signal circuit of the BCM and a battery positive voltage circuit.
  3. While probing, press the switch and hold the switch.

Does the test lamp illuminate?

Go to Step 18

Go to Step 16

16

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

Did you find and correct the condition?

Go to Step 27

Go to Step 15

17

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 27

Go to Step 23

18

Inspect for poor connections at the harness connector of the BCM. 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 27

Go to Step 24

19

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 27

Go to Step 25

20

Inspect for poor connections at the harness connector of the 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 27

Go to Step 26

21

Repair the open in the ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 27

--

22

Repair the interior park lamps supply voltage circuit.

Did you complete the repair?

Go to Step 27

--

23

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

Did you complete the replacement?

Go to Step 27

--

24

Important: Perform the setup procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 27

--

25

Replace the fog lamp relay.

Did you complete the replacement?

Go to Step 27

--

26

Replace both lamps. Refer to Front Fog Lamp Replacement .

Did you complete the replacement?

Go to Step 27

--

27

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

Fog Lamps Inoperative Export, Rear, Pickup

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn On the ignition, with the engine OFF.
  2. Turn ON the rear fog lamps.

Do the fog lamps operate properly?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

Is only one rear fog lamp inoperative?

Go to Step 7

Go to Step 4

4

At the inoperative lamp, test the rear fog lamp supply voltage circuit for a poor connection or an open. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 5

5

At the inoperative lamp, test the ground circuit for a poor connection or an open. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 15

6

  1. Turn the ignition ON with the engine OFF.
  2. Listen for an audible click at the rear fog lamp relay while pressing the rear fog lamp switch several times.

Do you hear a click from the relay?

Go to Step 16

Go to Step 7

7

  1. Remove the rear fog lamp relay.
  2. Connect a test lamp between the rear fog lamp relay control circuit at the relay connector and a battery positive ground circuit.
  3. Turn the rear fog lamps ON.

Does the test lamp illuminate?

Go to Step 14

Go to Step 8

8

Test the rear fog lamp relay control circuit for an open. Refer to Testing for Continuity in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 9

9

  1. Disconnect the BCM connector.
  2. Connect a test lamp between the rear fog lamp switch signal circuit and a battery positive voltage circuit.
  3. Momentarily press the rear fog lamp switch.

Does the test lamp illuminate when the switch is pressed?

Go to Step 13

Go to Step 10

10

Test the rear fog lamp switch signal circuit for an open. Refer to Testing for Continuity in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 11

11

  1. Disconnect the rear fog lamp switch connector.
  2. Connect a test lamp between the ground circuit of the rear fog lamp switch and a battery positive voltage circuit.

Does the test lamp illuminate?

Go to Step 12

Go to Step 17

12

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 22

Go to Step 18

13

Inspect for poor connections at the harness connector of the BCM. 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 22

Go to Step 19

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 Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 22

Go to Step 20

15

Inspect for poor connections at the harness connector of the 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 22

Go to Step 21

16

Repair the open in the rear fog lamp supply voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 22

--

17

Repair the open in the ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 22

--

18

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

Did you complete the replacement?

Go to Step 22

--

19

Important: Perform the setup procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 22

--

20

Replace the fog lamp relay.

Did you complete the replacement?

Go to Step 22

--

21

Replace the inoperative bulb. Refer to Rear Fog Lamp Bulb Replacement .

Did you complete the replacement?

Go to Step 22

--

22

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3

Fog Lamps Inoperative Export, Rear, Utility

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn On the ignition, with the engine OFF.
  2. Turn ON the rear fog lamps.

Does the rear fog lamp and the rear fog lamp indicator illuminate?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

  1. Turn the ignition ON with the engine OFF.
  2. Listen for an audible click at the rear fog lamp relay while pressing the rear fog lamp switch several times.

Do you hear a click from the relay?

Go to Step 4

Go to Step 6

4

At the inoperative lamp, test the rear fog lamp supply voltage circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 5

5

At the inoperative lamp, test the ground circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 14

6

  1. Remove the rear fog lamp relay.
  2. Connect a test lamp between the rear fog lamp relay control circuit at the relay connector and a battery positive ground circuit.
  3. Turn the rear fog lamps ON.

Does the test lamp illuminate?

Go to Step 13

Go to Step 7

7

Test the rear fog lamp relay control circuit for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 8

8

  1. Disconnect the BCM connector.
  2. Connect a test lamp between the rear fog lamp switch signal circuit and a battery positive voltage circuit.
  3. Momentarily press the rear fog lamp switch.

Does the test lamp illuminate when the switch is pressed?

Go to Step 12

Go to Step 9

9

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

Did you find and correct the condition?

Go to Step 20

Go to Step 10

10

  1. Disconnect the rear fog lamp switch connector.
  2. Connect a test lamp between the ground circuit of the rear fog lamp switch and a battery positive voltage circuit.

Does the test lamp illuminate?

Go to Step 11

Go to Step 15

11

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 20

Go to Step 16

12

Inspect for poor connections at the harness connector of the BCM. 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 20

Go to Step 17

13

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 20

Go to Step 18

14

Inspect for poor connections at the harness connector of the 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 20

Go to Step 19

15

Repair the open in the ground circuit to the rear fog lamp switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

--

16

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

Did you complete the replacement?

Go to Step 20

--

17

Important: Perform the setup procedure for the BCM.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 20

--

18

Replace the fog lamp relay.

Did you complete the replacement?

Go to Step 20

--

19

Replace the inoperative bulb. Refer to Rear Fog Lamp Bulb 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