DEFINITION: Noise originating from the blower motor and/or the air delivery system. No loss of battery or ground is occurring in the blower motor circuit. The blower control module and the blower motor are not exhibiting any intermittent internal shorts. For electrical diagnosis of the blower motor circuit, refer to Blower Motor Does Not Operate Properly in HVAC Systems - Automatic.

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check in HVAC Systems - Automatic

1. Sit inside the vehicle.
2. Close the vehicle doors and windows.
3. Turn ON the ignition, with the engine OFF.
4. Set the blower to high.
5. Set the temperature control to full cold.
6. Set the mode control so the air comes out the IP vents.
7. Cycle through all the blower motor speeds, modes (including outside air and recirc) and temperature control positions to determine where and when the noise occurs.
8. Attempt to define the type of noise:

•	Scrape, pop

•	Tick/click, chirping, groaning, scraping

•	Air rush/whistle

Is a scrape or pop noise evident when selecting modes or temperature settings (moving a mode or temperature valve)?

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Go to Step 8

Go to Step 3

Is a tick/click, chirping, groaning or scraping noise present -- constantly but decreases as blower motor speed is decreased, or only at start-up/intermttent -- in all modes?

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Go to Step 6

Go to Step 4

Is an air rush/whistle noise evident at all blower speeds?

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Go to Step 9

Go to Step 5

Is the complaint of an air rush/whistle noise only while the vehicle is moving?

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Go to Step 12

Go to Step 9

1. Inspect all the instrument panel, defroster and heater ducts/vents for blockage or foreign material.
2. Remove and repair as necessary.

Did you find and correct the condition?

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System OK

Go to Step 7

1. Remove the blower motor. Refer to Blower Motor and Fan Replacement .
2. Examine the blower motor, impeller and the blower motor cavity for the following conditions:

•	Missing or damaged blower motor to case seal

•	Deposits of foreign material

•	Wear spots

•	Cracked blades

•	Cracked hub

•	Loose impeller retainer

•	Loose or missing impeller balance weights

•	Improper impeller alignment

•	Roughness while spinning the impeller

3. Remove the material and/or repair or replace the blower motor assembly.
4. Install the blower motor and impeller assembly. Refer to Blower Motor and Fan Replacement .

Did you complete the repair?

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Go to Step 13

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1. Isolate the noise.
2. Inspect for a noisy actuator or binding valve door.
3. Repair as necessary.

Did you complete the repair?

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Go to Step 13

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1. Inspect all the instrument panel, defroster and heater ducts/vents for blockage or foreign material.
2. Remove and repair as necessary.

Did you find and correct the condition?

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System OK

Go to Step 10

1. Remove the blower motor. Refer to Blower Motor and Fan Replacement .
2. Examine the blower motor impeller and the blower motor cavity for the following conditions:

•	Deposits of foreign material

•	Wear spots

•	Cracked blades

•	Cracked hub

•	Loose impeller retainer

•	Improper impeller alignment

3. Remove the material and/or repair or replace the blower motor assembly.
4. Install the blower motor and impeller assembly. Refer to Blower Motor and Fan Replacement .
5. Operate the blower motor.

Is the noise still present.

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Go to Step 11

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The most likely cause of the noise is coming from either a misaligned duct in the instrument panel or within the HVAC module door valve/seals.

1. Remove the instrument panel assembly. Refer to Instrument Panel Carrier Support Replacement in Instrument Panel, Gauges and Console.
2. Inspect the ducts for proper alignment.
3. Inspect the valve door seals for loose or misaligned.
4. Repair or replace as necessary.

Did you complete the repair?

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Go to Step 13

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1. Inspect the base of the windshield and cowl area for air leaks.
2. Inspect the seals around the HVAC case at the front of dash.
3. Repair as necessary.

Did you complete the repair?

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Go to Step 13

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Operate the system in order to verify the repair.

Did you find and correct the condition?

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System OK

Go to Step 2