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. Place the fog lamp switch in the ON position.
  2. Measure voltage from ground to the headlamp switch connector terminal C1 terminal F (PPL).

Is battery voltage measured?

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Go to Step 4

Go to Step 3

3

Inspect CKT 34 (PPL) between the headlamp switch and splice S106.

Refer to Testing for Continuity in Wiring Systems.

Is the circuit OK?

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Go to Step 6

Go to Step 5

4

Inspect CKT 150 (BLK) for an open between the headlamp switch and splice S219. Refer to Testing for Continuity in Wiring Systems.

Is CKT 150 OK?

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Go to Step 6

Go to Step 5

5

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

Is the repair complete?

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Go to Step 7

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6

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 7

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7

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

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System OK.

Go to Step 2