I have a 98 sebring that for awhile now has been making some god-awful squealing sounds. I know the belts need replaced and am doing that. The thing that gets me is it's really noticeable and bad when I turn the blower-motor on. The air conditioner is turned off.

It is literally almost cause and effect. I notice it squealing, turn the blower off and not five seconds later it goes away. Mainly noticeable at slow speeds or idle.

I just don't want to replace the belts and have them get torn up by something causing them to drag or slip. Thanks.

 

There should be no connection between a squealing belt and the heater blower EXCEPT if the A/C is kicking in and out with the blower switch. You insist the A/C is off so unless the A/C kicks in as part of the Defrost function, there should be no connection whatsoever. It's exceedingly unlikely that the current draw from the blower motor would cause the alternator belt to squeal if it wasn't already squealing.
Regardless, replace and properly tension the belts and most probably, the squealing will go away.

 

Could there be a problem with the blower motor itself? If you turn on the blower with the engine off, do you still hear the noise?