GM Service Manual Online
For 1990-2009 cars only

Backup Lamp Inoperative - One Lamp Domestic

Step

Action

Value(s)

Yes

No

1

Was the Backup Lights System Check performed?

--

Go to Step 2

Go to Backup Lamp System Check

2

Is the left backup lamp operative?

--

Go to Step 10

Go to Step 3

3

  1. Remove the bulb from the left backup lamp.
  2. Connect a J 39200 DMM between the left backup lamp connector socket, cavity G, and ground.

Is continuity present?

--

Go to Step 5

Go to Step 4

4

Repair the open in CKT 150 (BLK) between the left backup lamp and ground G400.

Is the left backup lamp operative?

--

Go to Step 9

Go to Step 5

5

  1. Disconnect connector C1 at the backup lamp switch.
  2. Connect a J 39200 DMM between backup lamp switch connector C1, cavity F, and the left backup lamp switch connector socket, cavity A.

Is continuity present?

--

Go to Step 6

Go to Step 8

6

  1. Inspect the left backup lamp bulb.
  2. Replace the bulb, as necessary.

Is the left backup lamp operative?

--

Go to Step 9

Go to Step 7

7

Replace the left backup lamp socket.

Is the left backup lamp operative?

--

Go to Step 9

Go to Step 8

8

Repair the open in CKT 24 (LT GRN) between splice S409 and the left backup lamp.

Are both of the backup lamps operative?

--

Go to Backup Lamp System Check

Go to Step 10

9

Is the right backup lamp operative?

--

Go to Backup Lamp System Check

Go to Step 10

10

  1. Remove the bulb from the right backup lamp.
  2. Connect a J 39200 DMM between the right backup lamp connector socket, cavity G, and ground.

Is continuity present?

--

Go to Step 12

Go to Step 11

11

Repair the open in CKT 250 (BLK) between the right backup lamp and ground G401.

Is the right backup lamp operative?

--

Go to Backup Lamp System Check

Go to Step 12

12

  1. Disconnect connector C1 at the backup lamp switch.
  2. Connect a J 39200 DMM between backup lamp switch connector C1, cavity F, and the right backup lamp switch connector socket, cavity A.

Is continuity present?

--

Go to Step 13

Go to Step 15

13

  1. Inspect the right backup lamp bulb.
  2. Replace the bulb, as necessary.

Is the right backup lamp operative?

--

Go to Backup Lamp System Check

Go to Step 14

14

Replace the right backup lamp socket.

Is the right backup lamp operative?

--

Go to Backup Lamp System Check

Go to Step 15

15

Repair the open in CKT 24 (LT GRN) between splice S409 and the right backup lamp.

Is the right backup lamp operative?

--

Go to Backup Lamp System Check

--

Backup Lamp Inoperative - One Lamp Export

Step

Action

Value(s)

Yes

No

1

Did you perform the Backup Lights System Check?

--

Go to Step 2

Go to Backup Lamp System Check

2

  1. Connect an unpowered test lamp between backup lamp switch connector C1 Cavity C and ground.
  2. Place the ignition switch in RUN.

Did the test lamp light?

--

Go to Step 3

Go to Step 4

3

  1. Set the park brake.
  2. Place the transmission selector in reverse.
  3. Connect an unpowered test lamp between backup lamp switch connector C1 cavity F and ground.

Did the test lamp light?

--

Go to Step 5

Go to Step 6

4

Repair the open in CKT 139 (PNK) between the IP fuse block and the backup lamp switch.

Is the repair complete?

--

Go to Backup Lamp System Check

--

5

  1. Remove the backup lamp.
  2. Connect an unpowered test lamp between cavity B of the backup lamp connector and ground.

Did the test lamp light?

--

Go to Step 7

Go to Step 8

6

Adjust or replace the park/neutral position switch.

Is the repair complete?

--

Go to Backup Lamp System Check

--

7

Connect an unpowered test lamp between cavity B and cavity A of the backup lamp connector.

Did the test lamp light?

--

Go to Step 9

Go to Step 10

8

Repair the open in CKT 24 (LT GRN) between backup lamp connector cavity B and backup lamp switch connector C1 cavity F

Is the repair complete?

--

Go to Backup Lamp System Check

--

9

Replace the backup lamp.

Is the repair complete?

--

Go to Backup Lamp System Check

--

10

Repair the open in CKT 250 (BLK) between backup lamp connector cavity A and ground G401.

Is the repair complete?

--

Go to Backup Lamp System Check

--