GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Schematics

1

Did you perform the Lighting Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Turn ON the underhood lamp lamp.

Does the system operate normally?

Go to Testing for Electrical Intermittents in Wiring Systems

Go to Step 3

3

Do any courtesy lamps operate correctly?

Go to Step 4

Go to Courtesy Lamps Inoperative

4

Remove and inspect the bulb.

Is the bulb okay?

Go to Step 5

Go to Step 7

5

  1. Disconnect the lamp connector.
  2. Connect a test lamp between the courtesy lamps supply voltage circuit of the underhood lamp and a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 9

6

Connect a test lamp between the ground circuit of the underhood lamp and a battery positive voltage circuit.

Does the test lamp illuminate?

Go to Step 8

Go to Step 10

7

Inspect for poor connections at the harness connector of the bulb. 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 13

Go to Step 11

8

Inspect for poor connections at the harness connector of the lamp assembly. 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 13

Go to Step 12

9

Repair the open in the courtesy lamps supply voltage circuit between the underhood lamp and the body wiring harness junction block. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

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10

Repair the ground circuit of the underhood lamp. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

11

Replace the bulb as necessary.

Did you complete the replacement?

Go to Step 13

--

12

Replace the lamp assembly. Refer to Underhood Lamp Replacement .

Did you complete the replacement?

Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3