GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Verify that the backup lamps are always on.

Do the backup lamps operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Is the vehicle equipped with a manual transmission?

Go to Step 5

Go to Step 4

4

Use the scan tool to check if there are any codes set in the current or history Powertrain DTC Information.

Are any codes present?

Go to the Diagnostic System Check in the appropriate Transmission Section

Go to Step 7

5

  1. Disconnect the backup lamp switch connector.
  2. Turn ON the ignition, with the engine OFF.

Do the backup lamps illuminate?

Go to Step 6

Go to Step 9

6

Test the backup lamp signal circuit of the body control module (BCM) for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

Test the backup lamp supply voltage circuit of the BCM for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

8

Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace backup lamp switch. Refer to the following:

    •  Backup Lamp Switch Replacement for the NV 3500 transmission
    •  Backup Lamp Switch Replacement for the NV 4500 transmission

Did you complete the replacement?

Go to Step 11

--

10

Replace the BCM. Refer to Control Module References .

Did you complete the replacement?

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3