# brief AC "buzzing" noise when starting the car in hot weather?



## jaisonline (Mar 24, 2002)

since the weather has been hot of late (even in the northeast), i began noticing a strange noise coming from the the climate control unit area.

when i start the car with the AC (auto or manual mode with the fan on at least on 4 (====) bars) and after it's been sitting for a few hrs on a HOT day, I briefly (2-3 secs) hear an electronic buzzing/humming noise from the climate control area. i can actually repeat the problem if i turn off the car and start it again.

note: this noise doesn't occur 100% of the time. maybe 10-30% of the time but other people have noticed it while in my car so at least i know i'm not hearing things.

i will mention this to the my service rep when i take the car in for the next oil change (due in 3000 miles) but i was just curious if anyone ALSO experienced this noise and if so, what did DID the dealer replace to fix it.

*UPDATE: I only hear the noise when I turn the key in the ignition to start the car. once i'm done turning the key and the engine has fully cranked over/started), the noise goes away.*


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## The HACK (Dec 19, 2001)

A couple of possiblities I can offer, but they're just wild guesses since there's no way to offer an objective diagnosis without seeing an touching the car.

1) End stage resistor: When my end stage resistor blew, before it completely failed it would make a high-pitched, electric whining sound upon start-up and when it got worse, do it all the time when the climate control is on regardless of the AC's on or not.

2) Check your refrigerant hoses...See if you can spot any signs of leakage. My wife's AC hose developed a slow leak, and when the AC is switched on I can hear a brief hiss (10-20 seconds) and it will fade away. Eventually all the refrigerant leaked out and the AC stopped cooling.


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## Kaz (Dec 21, 2001)

That's just the foot/face/glass vent actuators moving around. If you have the system set to full auto, listen carefully and it'll make little buzzing noises all the time as it adjusts airflow between the various sets of vents.


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## jaisonline (Mar 24, 2002)

hey hack,

i will check for any leaks but you know, your "1st description" seems to be RIGHT ON TARGET. I only hear the noise when I turn the key in the ignition to start the car...



The HACK said:


> *1) End stage resistor: When my end stage resistor blew, before it completely failed it would make a high-pitched, electric whining sound upon start-up and when it got worse, do it all the time when the climate control is on regardless of the AC's on or not. *


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