GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Heater Blower Controls System Check?

--

Go to Step 2

Go to Heater Blower Controls System Check

2

  1. Place the ignition switch in the RUN position.
  2. Place the rear air conditioning (A/C) switch in the MEDIUM position.
  3. Use a test lamp J 35616-200 in order to backprobe from the rear A/C resistor pack CKT 1072 (LT BLU) cavity A to ground.

Did the test lamp light?

--

Go to Step 3

Go to Step 4

3

Inspect for a poor connection at the rear A/C resistor pack.

Does a poor connection exist?

--

Go to Step 9

Go to Step 5

4

Use a test lamp J 35616-200 in order to backprobe from the rear A/C switch CKT 1072 (LT BLU) cavity B to ground.

Did the test lamp light?

--

Go to Step 6

Go to Step 7

5

Replace the rear A/C resistor pack.

Refer to Auxiliary Blower Motor Resistor Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

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6

Repair the open in CKT 1072 (LT BLU) between the rear A/C switch and the rear A/C resistor pack.

Is the repair complete?

--

Go to Heater Blower Controls System Check

--

7

Inspect for a poor connection at the rear A/C switch.

Did you find a poor connection?

--

Go to Step 9

Go to Step 8

8

Replace the rear A/C switch. Refer to Accessory Switch Replacement .

Is the repair complete?

--

Go to Heater Blower Controls System Check

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9

Repair the poor connection.

Is the repair complete?

--

Go to Heater Blower Controls System Check

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