GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.

1

  1. Turn the ignition switch to the ON position.
  2. Disconnect the park/neutral position switch connector C1.
  3. Connect a test lamp between terminal B of connector C1 and ground.

Does the test lamp light?

--

Go to Step 2

Go to Step 3

2

Connect a fused jumper between terminal B and terminal F of connector C1 of the park/neutral position switch.

Do the backup lamps light?

--

Go to Step 4

Go to Step 5

3

Backprobe the underhood junction block connector C1 with a test lamp between terminal F5 and ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 7

4

Inspect the adjustment of the transaxle range switch. If the adjustment is OK, replace the park/neutral position switch.

Is the repair complete?

--

Go to Backup Lamp System Check

--

5

  1. Reconnect the park/neutral position switch connector C1.
  2. Place the transaxle in the REVERSE position.
  3. Backprobe the right IP junction block connector C2 with a test lamp between terminal B11 and ground.

Does the test lamp light?

--

Go to Step 8

Go to Step 9

6

Repair the open in CKT 539 between the underhood junction block and the transaxle range switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--

7

Replace the underhood junction block. Refer to Underhood Fuse Block Replacement in Engine Electrical.

Is the repair complete?

--

Go to Backup Lamp System Check

--

8

Replace the right IP junction block.

Is the repair complete?

--

Go to Backup Lamp System Check

--

9

Repair the open in CKT 24 between the park/neutral position switch and the right IP junction block. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Backup Lamp System Check

--