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 rear marker, license and tail lamps are inoperative.

Do the rear marker, license and 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

Do the Front Park and Marker Lamps operate properly?

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Go to Step 4

Go to Park, Tail and Side Marker Lamps Inoperative

4

Connect a test lamp from ground to the voltage supply terminal of the inoperative lamp socket. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

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Go to Step 5

Go to Step 7

5

Connect a test lamp between the voltage supply terminal and the ground terminal of the inoperative lamp socket. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 8

6

Replace the inoperative bulb.

Is the repair complete?

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Go to Step 9

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7

Locate and repair the open, high resistance or short to ground in CKT 2509 (BRN), 2109 (BRN) or CKT 2609 (BRN). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 9

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8

Locate and repair the open or high resistance in the ground CKT 1750 (BLK) or CKT 2250 (BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3