GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The blower motor is inoperative in all speed positions.

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the blower motor switch in each speed position.

Does the blower motor operate in any of the speed positions?

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Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. With the scan tool observe the Commanded Blower parameter in the HVAC Systems Automatic data list.
  2. Place the blower motor switch from the minimum speed position to the maximum.

Does the scan tool indicate that the Commanded Blower parameter is within the specified value?

0-100%

Go to Step 4

Go to Step 9

4

  1. Turn OFF the ignition.
  2. Disconnect the blower motor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the blower motor supply voltage circuit and the blower motor ground circuit.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 5

5

Test the battery positive voltage circuit and the ground circuit of the blower motor for high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 12

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6

  1. Connect a test lamp between the blower motor supply voltage circuit and the blower motor control circuit.
  2. Place the blower motor switch from the minimum speed position to the maximum.

Does the test lamp illuminate and change intensity?

--

Go to Step 8

Go to Step 7

7

Test the blower motor speed control circuit of the HVAC control module for high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Inspect for poor connections at the harness connector of the blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Replace the blower motor. Refer to Blower Motor Replacement .

Did you complete the replacement?

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Go to Step 12

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11

Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

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Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 2