GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting Systems Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Connect a scan tool to the data link connector (DLC).
  2. Inspect the IPC input: fog lamps switch.

Does the fog lamps switch operate properly?

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Go to Step 3

Go to Step 7

3

Remove the fog lamp relay from the underhood relay center.

Do the fog lamps turn off?

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Go to Step 4

Go to Step 10

4

  1. Re-install the fog lamp relay.
  2. Disconnect the body control module (PZM) connector C2.

Are the fog lamps on?

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Go to Step 5

Go to Step 6

5

Inspect CKT 1317 (DK GRN/WHT) for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.

Is CKT 1317 OK?

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Go to Step 12

Go to Step 13

6

Replace the body control module (PZM). Refer to Body Control Module Replacement in Body Control Systems.

Is the body control module replacement complete?

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Go to Step 14

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7

Disconnect the headlamp switch connector C1.

Do the fog lamps turn off?

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Go to Step 8

Go to Step 9

8

Replace the headlamp switch. Refer to Headlamp Switch Replacement in Lighting Systems.

Is the headlamp switch replacement complete?

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Go to Step 14

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9

Inspect CKT 192 (ORN) for a short to ground. Refer to Testing for Short to Ground in Wiring Systems.

Is CKT 192 OK?

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Go to Step 11

Go to Step 13

10

Repair the short to voltage in CKT 34 (PPL). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 14

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11

Replace the instrument cluster (IPC). Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the IPC replacement complete?

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Go to Step 14

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12

Replace the fog lamp relay.

Is the repair complete?

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Go to Step 14

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13

Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 14

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14

Operate the system in order to verify the repair. Did you correct the condition?

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System OK.

Go to Step 2