DEFINITION: A constant air rush noise is typical of all heater systems when operating on HI blower. Some systems and modes may be louder than others. If possible, check a similar vehicle to determine whether the noise is typical or excessive.

1

1. Sit in the vehicle.
2. Close the doors and the windows.
3. Turn ON the ignition.
4. Set the blower speed to HIGH and the temperature to COLD.
5. Cycle through the blower speeds, modes, and temperature settings in order to find the noise.

Is the blower noise constant at high blower speeds or certain modes but can be eliminated at lower speeds or in other modes?

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Go to Step 10

Go to Step 2

Check for motor and fan vibration at each blower speed by feeling the blower armature.

Is the vibration excessive?

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Go to Step 5

Go to Step 3

1. Remove the blower motor and the fan assembly. Refer to Blower Motor and Fan Replacement .
2. Check for any foreign material at the orifice of the blower inlet.

Did you find any foreign material at the blower orifice?

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Go to Step 4

Go to Step 5

Remove any foreign material from the orifice of the blower inlet.

Is the procedure complete?

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System OK

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1. Inspect the blower fan for wear spots, cracked blades, or a cracked hub.
2. Inspect the blower case for wear spots.

Did you find any blower components faulty?

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Go to Step 6

Go to Step 7

Correct all of the blower components that show signs of excessive wear. Refer to Blower Motor and Fan Replacement .

Is the procedure complete?

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System OK

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1. Lubricate the blower motor.
2. Install the blower motor. Refer to Blower Motor and Fan Replacement .
3. Recheck the blower motor operation.

Is the blower motor still noisy?

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Go to Step 8

System OK

1. Replace the blower motor assembly. Refer to Blower Motor and Fan Replacement .
2. Recheck the blower motor operation.

Is the blower motor still noisy?

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Go to Step 9

System OK

Reinstall the original motor.

Is the installation complete?

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Go to Step 10

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1. Set the blower speed to the HIGH position.
2. Check the blower operation for different temperature positions (from full hot to full cold) in all modes.

Is the blower motor noisy in all modes and in all temperature positions?

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Go to Step 11

Go to Step 12

1. Check for obstructions or foreign material between the blower fan and the temperature valve.
2. Remove any obstructions.

Is the procedure complete?

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Go to Step 16

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Is the blower motor noisy in all modes but not all temperature positions?

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Go to Step 13

Go to Step 14

1. Check the temperature actuator seals.
2. Repair or replace the temperature valve seals.

Is the procedure complete?

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Go to Step 16

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Is the blower motor noisy in all temperature positions but not in all modes?

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Go to Step 15

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1. Check the ducts of the noisy modes for obstructions.
2. Remove any obstructions from the ducts.
3. Check the air valve seals of a suspected mode.
4. Repair a faulty valve seal.

Is the procedure complete?

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Go to Step 16

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Recheck the blower operation.

Is the blower motor still noisy?

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Go to Step 10

System OK