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

Verify that the tail lamps are inoperative.

Do the tail lamps operate normally?

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

Go to Step 3

3

Turn the Multifunction Switch (Headlamp Switch) to the HEAD position.

Do the Side Marker Lamps function properly?

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Go to Step 4

Go to Marker Lamps Inoperative

4

  1. Remove the inoperative lamp.
  2. Inspect the filament.

Is the lamp open?

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Go to Step 5

Go to Step 6

5

Replace the lamp.

Is the repair complete?

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Go to Step 11

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6

Connect a test lamp from terminal B to ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

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Go to Step 10

Go to Step 7

7

Inspect LR PRK LP fuse and/or RR PRK LP fuse in the underhood fuse block.

Is the fuse good?

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Go to Step 9

Go to Step 8

8

Locate and repair CKT 2509 (BRN) (LH) and/or CKT 2609 (BRN/WHT) (RH) for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 11

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9

Locate and repair CKT 2509 (BRN) (LH) and/or CKT 2609 (BRN/WHT) (RH) for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 11

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10

Locate and repair CKT 1350 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3