GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you review the Stationary Windows Description and perform the necessary inspections?

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Go to Step 2

Go to Symptoms

2

Disconnect the RR defog fuse.

Did the rear window defogger grid turn off?

--

Go to Step 4

Go to Step 3

3

Locate and repair short to power in CKT 1093. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 7

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4

  1. Replace the RR defog fuse.
  2. Disconnect the heater and the A/C control module.

Did the rear window defogger grid turn off?

--

Go to Step 6

Go to Step 5

5

Locate and repair short to power in CKT 293. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 7

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6

Replace the Heater and A/C Control Module. Refer to Control Assembly Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

--

Go to Step 7

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7

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2