GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn the ignition to the ON position.
  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 Systems

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 9

Go to Step 4

4

Do the backup lamps operate normally?

Go to Step 6

Go to Step 5

5

  1. Disconnect the body control module (BCM) connector C1.
  2. Using a test lamp connected to ground, probe the CHMSL/Bkup fuse voltage supply circuit.

Does the test lamp illuminate?

Go to Step 8

Go to Step 7

6

Test the backup lamps supply voltage circuit for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Repair the CHMSL/Bkup Fuse voltage supply circuit for a poor connection open or an short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

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8

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the repair?

Go to Step 10

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9

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

Did you complete the repair?

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