GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Disconnect the rear window defogger relay.
  2. Turn the ignition switch on.

Is the defogger and heated mirrors still on?

--

Go to Step 7

Go to Step 2

2

Using a test light, probe between the rear window defogger relay connector terminal A1 and B+.

Is the test light on?

--

Go to Step 4

Go to Step 3

3

Replace the rear window defogger relay.

Is the repair complete?

--

Go to Defogger System Check

--

4

Inspect for a short to ground in circuit  193.

Is there a short to ground in circuit  193?

--

Go to Step 5

Go to Step 6

5

Repair the short to ground in circuit 193 (WHT).

Is the repair complete?

--

Go to Defogger System Check

--

6

Replace the HVAC control assembly . Refer to Control Assembly Replacement in HVAC System - Manual.

Is the repair complete?

--

Go to Defogger System Check

--

7

  1. Connect a test light between the rear window defogger relay connector terminal A2 and ground.
  2. Remove the fuse A5-A6 from the fuse block.

Is the test light on?

--

Go to Step 8

Go to Step 9

8

Repair a short to B+ in circuit  293.

Is the repair complete?

--

Go to Defogger System Check

--

9

Repair a short to B+ in circuit  267.

Is the repair complete?

--

Go to Defogger System Check

--