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. Place the ignition switch in the ON position.
  2. Place the automatic transmission in reverse.
  3. Verify that the backup lamps are inoperative.

Do the backup lamps operate normally?

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

Go to Step 3

3

Determine if one backup lamp is inoperative or both backup lamps are inoperative.

Is one backup lamp inoperative?

Go to Step 7

Go to Step 4

4

  1. Disconnect the automatic transmission range switch connector.
  2. Place the ignition switch in the ON position.
  3. Probe the battery positive voltage circuit of the automatic transmission range switch connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 11

5

Connect a fused jumper between the battery positive voltage circuit and the backup lamp supply voltage circuit of the automatic transmission range switch connector.

Do the backup lamps illuminate?

Go to Step 14

Go to Step 6

6

  1. Disconnect the LH backup lamp connector.
  2. Probe the backup lamp supply voltage circuit of the LH backup lamp connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 12

7

  1. Disconnect the inoperative backup lamp connector.
  2. Probe between supply voltage circuit and the ground circuit of the inoperative backup lamp connector with a test lamp.

Does the test lamp illuminate?

Go to Step 13

Go to Step 8

8

Test for an open or high resistance in the supply voltage circuit of the inoperative backup lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 9

9

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

Did you complete the repair?

Go to Step 15

--

10

Repair an open or high resistance in the ground circuit of the backup lamps. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 15

--

11

Repair an open or high resistance in the battery supply voltage circuit of the automatic transmission range switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 15

--

12

Repair an open or high resistance in the backup lamps supply voltage circuit of the backup lamps. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 15

--

13

Replace the inoperative lamp. Refer to Backup Lamp Bulb Replacement .

Has the repair been made?

Go to Step 15

--

14

Replace or adjust the automatic transmission range switch. Refer to Manual Shift Shaft Position Switch Replacement in Automatic Transmission.

Did you complete the repair?

Go to Step 15

--

15

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

Do the backup lamps operate properly?

System OK

Go to Step 3