Were you sent here from Symptoms or another diagnostic table?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

or

Symptoms - HVAC Systems - Automatic

Inspect the air inlet grille for debris.

Is debris present?

Go to Step 8

Go to Step 3

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

Is a noise evident during the blower operation?

Go to Step 4

Go to Step 11

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

Is excess vibration present?

Go to Step 6

Go to Step 5

Listen to the blower motor at each speed.

Is the blower motor making a squeaking or chirping noise?

Go to Step 9

Go to Step 11

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

Did you find any foreign material on the blower motor or blower motor impeller?

Go to Step 8

Go to Step 7

Inspect the blower motor for the following conditions:

1. Cracked blades
2. A loose impeller retainer
3. Improper impeller alignment

Did you find any of these conditions?

Go to Step 9

Go to Step 10

Remove the foreign material.

Is the action complete?

Go to Step 10

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Replace the blower motor. Refer to Blower Motor Replacement .

Is the repair complete?

Go to Step 11

--

Install the blower motor. Refer to Blower Motor Replacement .

Is the action complete?

Go to Step 11

--

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2