GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you review the Exterior Lighting System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Lighting Systems

2

  1. Turn ON the ignition.
  2. Place the gear selector lever in the REVERSE position.

Do the backup lamps illuminate?

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

Go to Step 3

3

Is only one backup lamp inoperative?

Go to Step 7

Go to Step 4

4

Inspect to determine if the vehicle is equipped with a manual transmission or an automatic transmission.

Is the vehicle equipped with a manual transmission?

Go to Step 5

Go to Step 6

5

  1. Disconnect the backup lamp switch.
  2. Connect a test lamp between the ignition 3 voltage circuit of the backup lamp switch and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

Go to Step 9

Go to Step 16

6

  1. Disconnect the park neutral position (PNP) switch.
  2. Connect a test lamp between the ignition 3 voltage circuit of the PNP switch and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

Go to Step 10

Go to Step 16

7

Connect a test lamp between the supply voltage circuit of the inoperative backup lamp and ground. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

Go to Step 8

Go to Step 17

8

Connect a test lamp between the ground circuit and supply voltage circuit of the inoperative backup lamp. Refer to Circuit Testing in Wiring Systems.

Does the test lamp illuminate?

Go to Step 12

Go to Step 18

9

Install a fused jumper across the ignition 3 voltage circuit and the backup lamps supply voltage circuit of the backup lamp switch.

Do the backup lamps illuminate?

Go to Step 13

Go to Step 15

10

Install a fused jumper across the ignition 3 voltage supply circuit and the backup lamps supply voltage circuit of the PNP switch.

Do the backup lamps illuminate?

Go to Step 11

Go to Step 15

11

Inspect the PNP switch for proper adjustment. Refer to Park/Neutral Position Switch Adjustment in Automatic Transaxle.

Did you find and correct the condition?

Go to Step 22

Go to Step 14

12

Inspect for poor connections at the harness connector of the inoperative backup lamp. 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 22

Go to Step 19

13

Inspect for poor connections at the harness connector of the backup lamp switch. 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 22

Go to Step 20

14

Inspect for poor connections at the harness connector of the PNP switch. 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 22

Go to Step 21

15

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

Did you complete the repair?

Go to Step 22

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16

Repair the open or the high resistance in the ignition 3 voltage circuit of the switch. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 22

--

17

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

Did you complete the repair?

Go to Step 22

--

18

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

Did you complete the repair?

Go to Step 22

--

19

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

Did you complete the replacement?

Go to Step 22

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20

Replace the backup lamp switch. Refer to Backup Lamp Switch Replacement in Manual Transmission - MM6 or Backup Lamp Switch Replacement in Manual Transmission - M49.

Did you complete the replacement?

Go to Step 22

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21

Replace the PNP switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transaxle.

Did you complete the replacement?

Go to Step 22

--

22

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2