GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2001 🢒 LeSabre 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Backup Lamps Inoperative

Backup Lamps Inoperative Automatic Transmission

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Listen for an audible click when the reverse relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

    2.

  2. Tests for voltage at the control side of the reverse relay.

    3.

  3. Verifies that the control module is providing ground to the reverse relay.

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List

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, with the engine OFF.
  2. Depress and hold the brake pedal.
  3. Move the gear selector through the gear ranges.
  4. Observe the backup lamps.
  5. Place the gear selector in the PARK position.
  6. Release the brake pedal.

Did the backup lamps operate properly?

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

Go to Step 3

3

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, command the reverse lamp relay ON and OFF from the rear integration module (RIM) Output Control data list.

Does the reverse lamp relay turn ON and OFF with each command?

Go to Step 6

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the reverse relay. Refer to Relay Replacement in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the reverse relay control side supply voltage circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 14

5

  1. Turn OFF the ignition.
  2. Connect a test lamp between the reverse relay control side supply voltage circuit and the reverse lamp relay control circuit.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the reverse lamp relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 12

Go to Step 9

6

Probe the reverse relay switch side supply voltage circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 15

7

Connect a 10-amp fused jumper between the reverse relay switch side supply voltage circuit and the backup lamp supply voltage circuit.

Do both of the backup lamps illuminate?

Go to Step 12

Go to Step 8

8
  1. Turn OFF the ignition.
  2. Remove the inoperative backup lamp bulb.
  3. Connect a test lamp between the backup lamp supply voltage circuit and the backup lamp ground circuit.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 11

Go to Step 10

9

Test the reverse lamp relay control circuit for an open or a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 13

10

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

Did you find and correct the condition?

Go to Step 20

Go to Step 16

11

Inspect for poor connections at the backup lamp bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 18

12

Inspect for poor connections at the reverse relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 17

13

Inspect for poor connections at the harness connector of the RIM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 19

14

Repair the open circuit in the reverse relay control side supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

--

15

Repair the open circuit in the reverse relay switch side supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 20

--

16

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

Did you complete the repair?

Go to Step 20

--

17

Replace the reverse relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 20

--

18

Replace the backup lamp bulb.

Did you complete the replacement?

Go to Step 20

--

19

Important:: After replacement, perform the setup procedure for the RIM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the RIM. Refer to Rear Integration Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 20

--

20

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2