99bluexj

I've researched numerous threads on here about engine compartment squeals and found some similarities to my issue which is that when the AC or defroster is on, and only while driving (not when idling), I will hear a squeal from under the hood. However, while trying to diagnose the issue today, I discovered that while idling with the defroster on my voltage drops from 14 to around 12 when the electric fan in front of the PS pump kicks on. Also, if I step on the gas and hold the RPMs steady at 1500 while in park, when the fan kicks on the RPMs climb to almost 2000 without moving the pedal. But as soon as the fan stops, the RPMs will return to 1500 again.

I'm really trying to think this one through with my limited experience but am stumped. Any ideas would be appreciated.

Thanks!

freegdr

the voltage drop is because your drawing more current the rpm change is done automaticly to raise and lower the idle to handle the loads on the motor

djb383

I would suggest tightening the serpentine belt a little, a loose belt will squeal when a/c compressor engages (defrost).

99bluexj

Thanks for the explanation and quick response. I understand the current draw but should it be that much? Is that normal and I've just never noticed it before?

99bluexj

Yes, that was first on my to do list when I then noticed the voltage drop and RPM changes that spooked and sidetracked me a bit. Thanks!