GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you review the HVAC operation and perform the necessary inspections?

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Go to Step 2

Go to Symptoms

2

  1. Turn ON the ignition, with the engine OFF.
  2. Disconnect the rear air conditioning (A/C) switch connector.

Did the rear heater blower motor stop running?

--

Go to Step 3

Go to Step 4

3

Replace the rear A/C switch. Refer to Control Switch Replacement - Auxiliary in Heating, Ventilation, and Air Conditioning.

Did you complete the replacement?

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Go to Step 9

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4

Disconnect the rear A/C resistor pack.

Did the rear heater blower motor stop running?

--

Go to Step 5

Go to Step 6

5

Connect a test lamp between the rear A/C switch CKT 1072 (LT BLU) cavity A to ground.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 8

6

Repair the short to voltage in CKT 1052 (ORN).

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 9

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7

Repair the short to voltage in CKT 1072 (LT BLU).

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 9

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8

Repair the short to voltage in CKT 1176 (YEL).

Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2