[Lcons31]

2004 Chevy Malibu 3.5L V6 - Once my car warms up it no longer has a problem but if I turn on the heater/defrost or ac while the thermostat dash needle is still under the middle it'll make a loud screeching sound. Once I turn it off it stops. I'm disabled but my son says the sound is coming from the front. We don't think it's the blower motor which is behind the glove compartment. Also because I'm on disability, I can't pay for a shop to fix this. If my son can do it, if it's fairly simple, I'd rather have him try but we don't know what it is. I hope someone can help me.

 

[DrivenDaily]

Please read this post and provide more info.

Likely the serp belt, possibly a weak belt tensioner.

 

[Lcons31]

The sound is not coming from that side. It's coming from very very front of car by bumper around fan area

 

[cp-the-nerd]

Pop the hood and record video of the sound and the location.