GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: Only the LH backup lamp illuminates.

1

Did you perform the Backup Lights Diagnostic System Check?

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Go to Step 2

Go to Backup Lamp System Check

2

  1. Turn on the ignition.
  2. Move the automatic transmission control lever to the REVERSE position.

Did the RH backup lamp illuminate?

--

Go to Step 7

Go to Step 3

3

  1. Disconnect the RH backup lamp connector.
  2. Use a DMM in order to measure the voltage between terminal B of the RH lamp connector and a known good ground.

Does the voltage measure near the specified value?

B+

Go to Step 5

Go to Step 4

4

  1. Locate an open or a high resistance in CKT MF1.
  2. Repair the open or the high resistance in CKT MF1.

Did you complete the repair?

--

Go to Step 9

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5

Use the DMM in order to measure the resistance between terminal A of the RH backup lamp connector and a known good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 9

Go to Step 6

6

  1. Locate an open or a high resistance in CKT F2.
  2. Repair the open or the high resistance in CKT F2.

Did you complete the repair?

--

Go to Step 8

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7

Use a DMM in order to measure the resistance between the terminal A of the LH backup lamp and a known good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 9

Go to Step 8

8

  1. Locate an open or high resistance in CKT F1.
  2. Repair the open or high resistance in CKT F1.

Did you complete the repair?

--

Go to Step 10

--

9

Replace the RH or LH backup lamp. Refer to Rear License Lamp Replacement in Lighting Systems.

Did you complete the repair?

--

Go to Step 10

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10

  1. Connect all connectors and components that were previously disconnected.
  2. Verify that the backup lamps operate properly.

Does the RH and LH backup lamps operate properly?

--

Go to Backup Lamp System Check

Go to Step 1