Check the blower electrical connections and the grounds. Refer to HVAC Blower Controls System Check .

Is the action complete?

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Go to Step 2

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1. Sit inside the vehicle.
2. Close all doors and windows.
3. Turn the ignition switch to ON.
4. Set the blower speed to HI.
5. Set the mode to VENT.
6. Set the temperature control to full COLD.
7. Cycle through all blower speeds, modes and temperature control positions to determine where noise occurs and where it does not occur.

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

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Go to Step 4

Go to Step 3

Listen to the blower again.

Is the blower making a squeal/screech noise at start-up only and/or sometimes intermittent?

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Go to Step 4

Go to Step 7

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

Is the vibration excessive?

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Go to Step 6

Go to Step 5

1. Remove the blower from blower case.
2. Check for foreign material at opening of blower intake.

Was foreign material found?

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Go to Step 10

Go to Step 6

1. Check the blower fan for the following conditions:

•	Wear spots

•	Cracked blades

•	Cracked hub

•	Loose fan retainer

•	Fan alignment

2. Check the blower case for wear spots.

Was any wear found?

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Go to Step 11

Go to Step 12

1. Set the blower speed to HI.
2. Check the full HOT to full COLD temperature positions in VENT, HEAT and DEFROST modes.

Is excessive blower noise in VENT mode only?

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Go to Step 13

Go to Step 8

Listen to the blower again.

Is excessive blower noise in HEAT and/or DEFROST modes only?

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Go to Step 14

Go to Step 9

Listen to blower again.

Is excessive blower noise in HEAT and/or DEFROST modes only?

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Go to Step 15

Go to Step 16

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

Is the action complete?

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Go to Step 17

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Repair the blower fan and/or blower case as necessary.

Is the action complete?

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Go to Step 17

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Replace the blower motor and fan.

Is the action complete?

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Go to Step 17

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1. Check the air ducts for obstructions and foreign material.
2. Check the vent door seals.
3. Repair as necessary.

Is the action complete?

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Go to Step 17

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1. Check the air ducts for obstructions and foreign material.
2. Check the heater and/or defroster door seals.
3. Repair as necessary.

Is the action complete?

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Go to Step 17

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

Is the action complete?

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Go to Step 17

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

Is the action complete?

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Go to Step 17

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Perform the functional test. Refer to Functional Check .

Is the action complete?

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System OK

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