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.
  2. Place the gear selector lever to the REVERSE position.

Do both backup lamps illuminate?

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

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 8

Go to Step 4

4

  1. Disconnect the Park Neutral Position (PNP) switch harness connector.
  2. Probe the battery positive supply voltage circuit of the PNP switch with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 9

5

Install a fused jumper across the ignition positive voltage supply circuit and the backup lamps voltage supply circuit.

Do the backup lamps illuminate?

Go to Step 6

Go to Step 7

6

Inspect and adjust the PNP switch. Refer to Park/Neutral Position Switch Adjustment in Automatic Transaxle.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

7

Repair a short to ground or open in the backup lamps supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring System.

Did you complete the repair?

Go to Step 11

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8

Repair the open in the inoperative backup lamp supply voltage circuit or ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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9

Repair the open in the battery positive supply voltage circuit of the PNP switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

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10

Replace the PNP switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transaxle - 4T65E.

Did you complete the replacement?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2