2000 Chevy Impala Heat & AC make noise when turned on.

KLMILUM112

MEMBER
2000 CHEVROLET IMPALA
6 CYL
FWD
AUTOMATIC
101,900 MILES

About 3 months ago, my car's heat & ac unit began to make noise when it is turned on. It starts as a loud whistling noise and than quiets down, but the noise is still audible. I am still able to get heat and cool air, but it just takes a little longer (for the heat) than usual. My dad is thinking the blower is going out. I'm not sure and I don't want to take it to a mechanic until I know for sure what is the problem with the unit.

3 Replies

IMPALASS

MECHANIC
3,112 POSTS

Hello -

To better assist you is your model just the Impala or the LS and what is your engine size in liter?

If I understand you correctly you only hear the noise when selecting the blower fan.....

It works at all speed but not much air output?

The noise....... Is it coming from the passenger side, under the dash above where your feet would be?

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Thursday, December 17th, 2009 AT 8:25 PM

KLMILUM112

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2 POSTS

You are very much welcome for the donation.

The model of the car is just the regular Impala. The engine size ( I think it may be a 3.4L, that's what they always put in at autozone; i'm not sure really.)

The noise is only heard when I turn the blower fan on, not when I select the temperature. It works at all speed, but not much air comes through the openings.

The noise sounds like it's coming from the middle passenger vents ( like my car has the heat/ac unit, then above it is the radio, and on the side of the radio are the air vents/openings). It is a whistling sound.

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Friday, December 18th, 2009 AT 8:46 AM

IMPALASS

MECHANIC
3,112 POSTS

Hello -

Is the engine operating temperature reading normal?

Do you have a volt meter? You can do this check yourself if you do.........

Passenger side where the feet would be, right above there, remove the sound insulator panel under the dash. You may need to pull the carpet away a little. You should see the bottom of the fan motor with the fan connector. Remove the plug and turn the fan on and see which wire is the positive. In the wiring diagram I have they both are black. Then you would match that to the motor. Then take 12v positive and a ground and touch both pins on the motor to see if the fan motor spins.

Do you have dual zone climate control?

Does the air come out the same in all the other vents too or is it stronger say in defrost or on the floor but not the same on the dash vents.

You also may have a blower motor control module.......

If you can do any other checks on the system that would help. That is in high heat with the selector on defrost, the fan works the same in all speeds or not in some or never goes on high but the other speeds work okay. Then on vent do the same test etc.

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Friday, December 18th, 2009 AT 8:08 PM