Humming noise when ac on

Hey guys my truck makes a low humming noise when ac is on under acceleration or while decelerating at lower rpms. This only happen when is really hot outside. Also after driving for 10 min or so no more noise or if I turn off the ac no more noise either. Any ideas???

 

I have a 2002 Tacoma. At cold start ups it Squeaks on and off until it warms up then it's fine. Not sure what's the cause tho

 

My 99 does the same thing. It's the blower fan. It's not a big deal if you can deal with the noise.

 

So it is normal then????? No fix need it??

 

remove your blower motor. there may be debris in there that's causing an imbalance and the vibrations. if not, clean it with some electronics cleaner and reinstall it. outside only. don't clean inside the motor.