GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Fog Lights System Check?

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Go to Step 2

Go to Fog Lights System Check

2

  1. Turn the ignition switch to the ON position. Do not start the vehicle.
  2. Connect the scan tool.
  3. Inspect the system for DTCs in the body control module (BCM).

Does the scan tool show any DTCs?

--

Go to Diagnostic System Check - Body Control System in Body Control System

Go to Step 3

3

Turn the park lamps ON.

Do the park lamps light?

--

Go to Step 4

Go to Exterior Lights System Check

4

  1. Press and hold the fog lamp switch in the ON position.
  2. Use the scan tool in order to read the switch status in the BCM. Refer to Scan Tool Data List in Body Control System.

Does the scan tool indicate that the switch is ON?

--

Go to Step 12

Go to Step 5

5

  1. Disconnect the fog lamp switch.
  2. Connect a fused jumper wire between fog lamp switch terminal E and ground.
  3. Use the scan tool in order to read the switch status in the BCM.

Does the scan tool show that the switch is ON?

--

Go to Step 7

Go to Step  6

6

  1. Connect a fused jumper wire between terminal E to ground of the fog lamp switch.
  2. Use the scan tool to in order to read the switch status in the BCM.

Does the scan tool show that the switch is closed?

--

Go to Step 11

Go to Step 8

7

Replace the fog lamp switch.

Is the repair complete?

--

Go to Fog Lights System Check

--

8

  1. Turn the park lamps OFF.
  2. Turn the ignition switch to the OFF position.
  3. Disconnect the BCM.
  4. Use a J 39200 digital multimeter (DMM) in order to inspect the continuity of CKT 192 (ORN) between terminal E of the fog lamp switch and terminal B5 of connector C3.

Is continuity present?

--

Go to Step 10

Go to Step 9

9

Locate and repair the open in CKT 192 (ORN) between the switch and the BCM.

Is the repair complete?

--

Go to Fog Lights System Check

--

10

Replace the BCM.

Is the repair complete?

--

Go to Fog Lights System Check

--

11

Locate and repair the open in CKT 1050 (BLK) between the switch and ground.

Is the repair complete?

--

Go to Fog Lights System Check

--

12

  1. Disconnect the fog lamp relay.
  2. Connect the test lamp between the fog lamp relay terminal 5 and battery.

Does the test lamp light?

--

Go to Step 14

Go to Step 13

13

Repair the damaged connections in the underhood fuse block. If no damaged connections are found, replace the underhood fuse block.

Is the repair complete?

--

Go to Fog Lights System Check

--

14

Use a J 39200 digital multimeter (DMM) in order to test for continuity of CKT 1317 from the fog lamp relay terminal 2 to the BCM connector C2 terminal A7.

Is continuity present?

--

Go to Step 16

Go to Step 15

15

Locate and repair the open in CKT 1317.

Is the repair complete?

--

Go to Fog Lights System Check

--

16

  1. Turn the ignition switch to the ON position.
  2. Turn the park lamps ON.
  3. Connect a test lamp from terminal 1 of the fog lamp relay to ground.

Does the test lamp illuminate?

--

Go to Step 17

Go to Step 13

17

Replace the fog lamp relay.

Is the repair complete?

--

Go to Fog Lights System Check

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