GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Inspect the B/U LP fuse for an open.

Is the fuse open?

--

Go to Step 7

Go to Step 2

2

  1. Disconnect the PARK/NEUTRAL position switch connector C1.
  2. Using a test lamp, probe between the park/neutral position 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 fused jumper (15A) to the park/neutral position switch harness connector C1, between terminal B and terminal  F.

Do the backup lamps light?

--

Go to Step 5

Go to Step 4

4

Repair the poor connection or open in circuit 24 between the park/neutral position switch harness connector C1 terminal F and C400 terminal D.

Has the repair been made?

--

Go to Backup Lamp System Check

--

5

Adjust/Replace the PARK/NEUTRAL switch. Refer to Park/Neutral Position Switch Adjustment or Park/Neutral Position Switch Replacement in Automatic Transaxle -- 4T65-E.

Has the repair been made ?

--

Go to Backup Lamp System Check

--

6

Repair the poor connection or 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

--