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?

--

Go to Step 2

Go to Symptoms

2

Inspect the LO BLOWER fuse in the fuse block.

Is the LO BLOWER fuse open?

--

Go to Step 3

Go to Step 6

3

Inspect for a short to ground in circuit 141 (BRN). Refer to Testing for Short to Ground in Wiring Systems.

Is a short to ground in the circuit?

--

Go to Step 4

Go to Step 5

4

Locate and repair the short to ground in circuit 141 (BRN). Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 14

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5

Replace the Heater-A/C control. Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to Step 14

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6

  1. Disconnect the heater-A/C control connector C1.
  2. Turn the ignition switch to the ON position.
  3. Use a test lamp to backprobe between the heater-A/C control connector C1 terminal B and ground.

Does the test lamp light ?

--

Go to Step 7

Go to Step 3

7

  1. Reconnect the heater-A/C control connector C1.
  2. Disconnect the blower motor connector.
  3. Turn the ignition switch to the ON position.
  4. Turn the heater-A/C control switch to HI.
  5. Use a test lamp in order to backprobe between the blower motor connector terminal A and ground.

Does the test lamp light?

--

Go to Step 8

Go to Step 11

8

Use a test light in order to backprobe between the blower motor connector terminal A and terminal B.

Does the test lamp light?

--

Go to Step 9

Go to Step 10

9

Replace the blower motor. Refer to Blower Motor and Fan Replacement .

Is the repair complete?

--

Go to Step 14

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10

  1. Disconnect the blower motor resistor connector.
  2. Using a test light, probe between the blower motor resistor harness connector terminal E and B+.
  3. Does the test lamp light?

--

Go to Step 11

Go to Step 12

11

Replace the blower motor resistor. Refer to Blower Motor Resistor Replacement in Heating, Ventilation, and Air Conditioning.

Is the repair complete?

--

Go to Step 14

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12

Repair poor connector or open in circuit 150 (BLK) between the blower motor resistor connector C1 terminal E and G200.

Is the repair complete?

--

Go to Step 14

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13

Repair a poor connection or an open in circuit 141 (BRN). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 14

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14

Verify that the system operates properly.

Does the system operate properly?

--

System OK

Go to Symptoms