GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Deffoger System Check?

--

Go to Step 2

Go to Defogger System Check

2

  1. Disconnect the HVAC control module.
  2. Place the ignition switch in the RUN position.
  3. Connect a test lampJ 35616-200 from CKT 1440 (ORN) at the HVAC control module connector C1 to ground.

Does the test lamp light?

--

Go to Step 4

Go to Step 3

3

Locate and repair an open in CKT 1440 (ORN) between the HVAC control module connector C1 and the underhood fuse-relay center.

Is the repair complete?

--

Go to Defogger System Check

--

4

Connect a test lampJ 35616-200 from CKT 141 (BRN) at the HVAC control module connector C1 cavity B to ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 5

5

Locate and repair an open in CKT 141 (BRN) between the HVAC control module connector C1 and the I/P fuse block.

Is the repair complete?

--

Go to Defogger System Check

--

6

Connect a test lamp from CKT 141 (BRN) at the HVAC control module connector C2 cavity E to ground.

Does the test lamp light?

--

Go to Step 8

Go to Step 7

7

Locate and repair an open in CKT 141 (BRN) between the HVAC control module connector C2 and S224.

Is the repair complete?

--

Go to Defogger System Check

--

8

Use an ohmmeter in order to probe the HVAC control module connector C1 CKT 1050 (BLK) to ground.

Is there continuity?

--

Go to Step 9

Go to Step 10

9

Replace the HVAC control module.

Is the repair complete?

--

Go to Defogger System Check

--

10

Locate and repair an open in CKT 1050 (BLK) between the HVAC control module connector C1 and G200.

Is the repair complete?

--

Go to Defogger System Check

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