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. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, command the Backup Lamp Relay Cmd. ON and OFF from the rear integration module (RIM) output controls data list.
  4. Listen for the backup lamp relay to click as it is cycled from ON to OFF.

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

Go to Step 5

Go to Step 3

3

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

Does the test lamp illuminate?

Go to Step 4

Go to Step 13

4

  1. Turn OFF the ignition.
  2. Connect a test lamp between the reverse lamp 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 Backup Lamp Relay ON and OFF.

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

Go to Step 11

Go to Step 8

5

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

Does the test lamp illuminate?

Go to Step 6

Go to Step 14

6

  1. Turn OFF the ignition.
  2. Connect a 10-amp fused jumper between the reverse lamp relay switch side supply voltage circuit and the backup lamp supply voltage circuit.
  3. Turn ON the ignition, with the engine OFF.

Do both backup lamps illuminate?

Go to Step 11

Go to Step 7

7

  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 10

Go to Step 9

8

Test the reverse lamp relay control circuit for an open, high resistance, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 19

Go to Step 12

9

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

Did you find and correct the condition?

Go to Step 19

Go to Step 15

10

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 19

Go to Step 17

11

Inspect for poor connections at the reverse lamp 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 19

Go to Step 16

12

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 19

Go to Step 18

13

Locate and repair an open or high resistance in the reverse lamp relay control side supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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14

Locate and repair an open or high resistance in the reverse lamp relay switch side supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 19

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15

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

Did you complete the repair?

Go to Step 19

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16

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

Did you complete the replacement?

Go to Step 19

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17

Replace the backup lamp bulb. Refer to Backup Lamp Replacement .

Did you complete the replacement?

Go to Step 19

--

18

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

Did you complete the replacement?

Go to Step 19

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19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2