GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the entire Backup Lights System Check?

--

Go to Step 2

Go to Backup Lamp System Check

2

  1. Disconnect the park/neutral position switch.
  2. Turn the ignition switch to the RUN position.
  3. Connect a DMM from the park/neutral position switch connector C1 cavity B (PNK) to ground.

Is the voltage within the specified range?

10-15V

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 539 (PNK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

6

Is the vehicle equipped with lamp monitoring?

--

Go to Step 7

Go to Step 9

7

  1. Disconnect the lamp monitor control module connector C1 and connector C2.
  2. Connect a fused jumper between the lamp monitor control module connector C2 cavity J (LT GRN) and connector C1 cavity G (GRY).

Do the backup lamps turn on?

--

Go to Step 8

Go to Step 10

8

Replace the lamp monitor control module. Refer to Instrument Panel Lamp Dimmer Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Backup Lamp System Check

--

9

Inspect the CKT 24 (LT GRN) wiring for an open or short to ground. Refer to Testing for Continuity and Testing for Short to Ground in Wiring Systems.

Is CKT 24 (LT GRN) OK?

--

Go to Step 11

Go to Step 12

10

Inspect the CKT 1524 (GRY) wiring for an open or short to ground. Refer to Testing for Continuity and Testing for Short to Ground in Wiring Systems.

Is CKT 1524 (GRY) OK?

--

Go to Step 9

Go to Step 12

11

Repair the open in CKT 1350 (BLK). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

12

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

Is the repair complete?

--

Go to Backup Lamp System Check

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