GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

DEFINITION: Noise originating from the blower motor.

1

Were you sent here from Symptoms or another diagnostic table?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual or to Symptoms - HVAC Systems - Automatic

2

  1. Sit inside the vehicle.
  2. Close the vehicle doors and windows.
  3. Turn ON the ignition switch, with the engine OFF.
  4. Cycle through all the blower motor speeds and modes in order to determine where noise occurs.

Is the noise evident during blower operations?

Go to Step 3

Go to Step 10

3

Does the noise vary with the blower speed?

Go to Step 4

Go to Step 10

4

Inspect for excess vibration at each blower motor speed by feeling the blower case.

Is excess vibration present?

Go to Step 5

Go to Step 10

5

  1. Remove the blower motor. Refer to Blower Motor Replacement .
  2. Inspect the blower motor for deposits of foreign material.

Did you find any foreign material on the blower motor?

Go to Step 7

Go to Step 6

6

Inspect the blower motor for the following conditions:

    • Cracked blades
    • A loose impeller retainer
    • Improper impeller alignment

Did you find any of these conditions?

Go to Step 8

Go to Step 9

7

Remove the foreign material.

Is the action complete?

Go to Step 10

--

8

Replace the blower motor. Refer to Blower Motor Replacement .

Is the action complete?

Go to Step 10

--

9

Install the blower motor. Refer to Blower Motor Replacement .

Is the action complete?

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2