GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the headlamp switch in the PARK position.

Do the license lamps operate properly?

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

Go to Step 3

3

Do the park lamps operate properly?

Go to Step 4

Go to Park Lamps Inoperative

4

  1. Turn OFF the ignition.
  2. Remove the inoperative license lamp.
  3. Connect a test lamp between the supply voltage circuit of the license lamp and a good ground.
  4. Turn ON the ignition, with the engine OFF.
  5. Turn ON the park lamps.

Did the test lamp illuminate?

Go to Step 5

Go to Step 7

5

Connect a test lamp between the supply voltage circuit of the license lamp and the ground circuit of the license lamp.

Does the test lamp illuminate?

Go to Step 6

Go to Step 8

6

Inspect for poor connections at the inoperative license lamp. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

7

Repair an open or short to ground in the supply voltage circuit of the license lamps. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

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8

Repair an open or high resistance in the ground circuit of the license lamps. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

--

9

Replace the inoperative license lamp. Refer to Rear License Lamp Replacement .

Did you complete the replacement?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2