Humming noise from A/C

[bdd012]

whenever i turn on my A/C, i get a humming noise from under the hood on the passenger side. like a winding humming noise that lasts about 2 seconds and then stops. it only does it occasionally. this happen to anyone else or any ideas what it could be? thanks

[Sepiroth]

Reads to me like the compressor is cycling on and off as it should.

A general rule of thumb is if the compressor cycles more than 10 times in one minute, you're low on refrigerant.

[bdd012]

oh i guess i should have added that it only does it when i first turn it on. not continuely.

[WickedGoat]

Keep your eyes on it..... The A/C compressor shouldn't hum at all. It should just click every so often, this being the clutch cycling as it should. A few GTO's had to have compressors replaced because of humming that made them go bad.