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 decreased or eliminated at lower speeds or in other modes?

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Go to Step 2

Go to Step 4

1. Remove the blower assembly and check for obstructions or foreign material that may be causing the noise.
2. Remove any obstructing materials from the blower assembly.

Is the noise still present?

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Go to Step 3

System OK

Replace the blower assembly.

Is the repair complete?

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System OK

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Is the noise a squeal or a screech that occurs intermittently or at startup when the outside air temperature is cold and the blower speed is low?

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Go to Step 2

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