Did you perform the Heater Blower Controls System Check?

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Go to Step 2

Go to Heater Blower Controls System Check

Inspect all of the electrical connections and grounds for proper connections.

Is the condition of any of the connections in doubt?

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Go to Step 3

Go to Step 5

Use a voltmeter in order to inspect for constant voltage at the blower motor.

Is the voltage constant?

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Go to Step 5

Go to Step 4

Repair any connections as needed.

Did you complete the repairs?

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Go to Step 5

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1. Sit in the vehicle.
2. Close all of the doors and windows.
3. Turn the ignition switch to the ON position. Do not turn on the engine.
4. Set the blower control to the HIGH position.
5. Set the mode control to the VENT position.
6. Set the temperature control to the FULL COLD position.
7. Cycle through the following items:

•	The blower speeds

•

The modes

•	You may have to start the engine occasionally in order to change the mode.

•	The temperature valve positions

8. Determine the origin of the noise.
9. Determine the type of noise:

•	Air rush (see note)

•

Whine

•	Tick or click

•	Squeal or screech

•

Flutter

•

Rumble

•

Scrape

Is the noise consistent with the following conditions?

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Go to Step 6

Go to Step 17

1. Set the blower control to the HIGH position.
2. Set the temperature control to the FULL HOT position and the FULL COLD position in the following modes:

•

DEFROST

•

HEATER

•

VENT

Does the noise occur in ONLY ONE of the following modes?

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Go to Step 7

Go to Step 11

Inspect the ducts for obstructions or foreign materials.

Are the ducts obstructed?

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Go to Step 8

Go to Step 9

Remove the obstruction or foreign material from the ducts.

Does the noise persist?

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Go to Step 9

Go to Heater Blower Controls System Check

Inspect the valve seal.

Is the valve seal in need of repair or replacement?

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Go to Step 10

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Repair or replace the valve seal as needed.

Does the noise persist?

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Go to Heater Blower Controls System Check

Does the noise occur in all of the modes but not all of the temperature positions?

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Go to Step 12

Go to Step 14

Inspect the temperature valve seals.

Are the valve seals in need of repair or replacement?

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Go to Step 13

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Repair or replace the valve seals as needed.

Does the noise persist?

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Go to Heater Blower Controls System Check

Does the noise occur in all of the modes and in all of the temperature positions?

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Go to Step 15

Go to Heater Blower Controls System Check

Inspect the system for obstructions or foreign materials between the fan and the temperature valve.

Are any components in need of repair or replacement?

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Go to Step 16

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Repair or replace the components as needed.

Does the noise persist?

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Go to Heater Blower Controls System Check

Is the noise consistent with one or more of the following conditions?

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Go to Step 18

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

Is the vibration excessive?

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Go to Step 21

Go to Step 19

Remove the blower motor and the fan assembly.

Inspect for foreign material at the orifice of the blower inlet.

Was an obstruction found?

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Go to Step 20

Go to Step 21

Repair or replace the components as needed.

Does the noise persist?

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Go to Heater Blower Controls System Check

Replace the motor and the fan assembly.

Does the noise persist?

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Go to Heater Blower Controls System Check

Important: A constant air rush noise is typical of all systems with the blower in the HIGH position. Some systems and modes (usually the DEFROSTER mode) are more noticeable than other systems and modes. Compare the noise with the noise in another vehicle (the same model, if possible) in order to determine if the noise is normal.