GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Inspect Fuse 29.

Is the fuse open?

--

Go to Step 7

Go to Step 2

2

Disconnect the Park Neutral Position (PNP) switch connector C1.

Using a test light, backprobe between the PNP switch harness connector C1 from terminal B and ground.

Does the test light illuminate?

--

Go to Step 3

Go to Step 6

3

Connect a 15 A fused jumper to the PNP switch harness connector C1, between terminal B and terminal F.

Are the backup lamps lit?

--

Go to Step 5

Go to Step 4

4

Check a poor connection or an open in circuit 24 between the transaxle range switch harness connector C1 terminal F and S927.

Is there a poor connection or an open in circuit 24?

--

Go to Step 8

Go to Step 9

5

Adjust or replace the PNP switch. Refer to Park/Neutral Position Switch Adjustment in Automatic Transaxle - 4T65-E.

Has the repair been made?

--

Go to Backup Lamp System Check

--

6

Repair a poor connection or an open in circuit 840.

Has the repair been made?

--

Go to Backup Lamp System Check

--

7

Repair a short to ground in circuit 840 or circuit 24.

Has the repair been made?

--

Go to Backup Lamp System Check

--

8

Repair a poor connection or an open in circuit 24 between the PNP switch harness connector C1 terminal F and S927.

Has the repair been made?

--

Go to Backup Lamp System Check

--

9

Repair a poor connection or an open in circuit 350 between S915 and G402.

Has the repair been made?

--

Go to Backup Lamp System Check

--