GM Service Manual Online
For 1990-2009 cars only

Backup Lamps Inoperative Buick

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. Disconnect the park/neutral position switch connector.
  2. Set the ignition switch to RUN.
  3. Measure the voltage to ground at the park/neutral position switch connector C1 cavity B (PNK).

Is the voltage within the specified range?

10-15 V

Go to Step 3

Go to Step 5

3

Connect a fused jumper between the park/neutral position switch connector C1 cavity B (PNK) and cavity F (LT GRN).

Do the backup lamps turn on?

--

Go to Step 4

Go to Step 6

4

Replace the park/neutral position switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transaxle-4T65-E.

Is the repair complete?

--

Go to Backup Lamp System Check

--

5

Repair the open or short to ground in CKT 139 (PNK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

6

Inspect CKT 24 (LT GRN) for an open between S432 and the park/neutral position switch. Refer to Testing for Continuity in Wiring Systems.

Is CKT 24 OK?

--

Go to Step 7

Go to Step 8

7

Repair the open in CKT 1250 (BLK) between S425 and G401. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

8

Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

Backup Lamps Inoperative Oldsmobile

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. Disconnect the park/neutral position switch connector.
  2. Set the ignition switch to RUN.
  3. Measure the voltage between the park/neutral position switch connector C114 cavity D (PNK) and ground.

Is the voltage within the specified range?

10-15 V

Go to Step 3

Go to Step 5

3

Connect a fused jumper between the park/neutral position switch connector C114 cavity D (PNK) and cavity F (LT GRN).

Do the backup lamps turn on?

--

Go to Step 4

Go to Step 6

4

Replace the park/neutral position switch. Refer to PNP Switch Replacement in Automatic Transaxle-4T80-E.

Is the repair complete?

--

Go to Backup Lamp System Check

--

5

Repair the open or short to ground in CKT 139 (PNK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

6

Test CKT 24 (LT GRN) for an open between S432 and the park/neutral position switch. Refer to Testing for Continuity in Wiring Systems.

Is CKT 24 OK?

--

Go to Step 7

Go to Step 8

7

Repair the open in CKT 1250 (BLK) between S425 and G401. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

8

Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--