Important:: A constant air rush noise is typical of high speed blower operation. Some systems and modes may be worse than others. If possible, inspect another similar vehicle of the same model in order to determine whether the noise is typical of the system as designed or excessive.

Did you perform the function test?

Go to Step 2

Go to Function Test

Inspect the blower electrical connections and grounds. Refer to HVAC Blower Control Schematics.

Is the repair complete?

Go to Function Test

Go to Step  3

1. Sit inside vehicle.
2. Close all of the doors and windows.
3. Turn ignition switch to the ON position
4. Set the blower speed to HIGH.
5. Set the mode control to the VENT position.
6. Set the temperature control to the coldest position.
7. Cycle through all of the blower speeds, modes, and temperature control positions to determine where the noise occurs and where it does not occur.
8. Try to determine the type of noise: air rush, whine, tick/click, squeal/screech, flutter, rumble or scraping noise.

Is the blower making a constant whine, tick/click, flutter or scraping noise, but lessens with a lower blower speed?

Go to Step 5

Go to Step  4

Is the blower making a squeal/screech noise at cold ambient temperatures or low blower speeds at start-up only and or intermittently?

Go to Step 5

Go to Step 11

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

Is the vibration excessive?

Go to Step 6

Go to Step 7

1. Remove the blower from the blower case. Refer to Blower Motor and Fan Replacement .
2. Inspect for foreign material at opening of blower intake.

Is foreign material present?

Go to Step 8

Go to Step 7

1. Inspect the blower fan for the following conditions:

•	Wear spots

•	Cracked blades

•	Cracked hub

•	A loose fan retainer

2. Inspect the fan alignment
3. Inspect the blower case for wear spots.

Is the blower case worn or damaged?

Go to Step 9

Go to Step 10

Remove the foreign material from the blower assembly. Repair as necessary.

Is the repair complete?

Go to Function Test

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Replace the blower case. Refer to HVAC Module Assembly Replacement .

Is the repair complete?

Go to Function Test

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Replace the blower motor and fan. Refer to Blower Motor and Fan Replacement .

Is the repair complete?

Go to Function Test

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1. The noise is constant at high blower speeds with some door combinations but can be eliminated at lower blower speeds or with other door combinations.
2. Set blower speed to HIGH.
3. Inspect the hottest to the coldest temperature positions in the VENT, the HEAT, and the DEFROSTER modes.

Is the excessive blower noise in all modes and all temperature positions?

Go to Step 15

Go to Step 12

Is excessive blower noise in all modes but not all temperature positions?

Go to Step 14

Go to Step 13

1. The noise is mode sensitive.
2. Inspect the air ducts for obstructions and foreign material.
3. Inspect the vent door seals.
4. Inspect the heater door seals.
5. Inspect the defroster door seals.
6. Repair as necessary.

Is the repair complete?

Go to Function Test

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1. Inspect the temperature door seals.
2. Repair as necessary.

Is the repair complete?

Go to Function Test

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1. Inspect the heater system for obstruction or foreign material between the blower fan and the temperature door.
2. Repair as necessary.

Is the repair complete?

Go to Function Test

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