fan or alter Belt squeels

Anyone know what may cause this problem..... my 03' neon the belt makes a loud squeeling noise when it turns on or when heater vents and lights turned on (night). When the squeeling starts to sound the car drops power..example ...when lights are on at nite it goes dimmer ..it only squeels for like 10-20 secs then it gaines back power.... what could be the problem ?

Thats always been a sign the alternator belt is not tight enough. Normally tightening the belt slightly will stop the squeal. If you changed that belt in the previous month or two, it could have loosened up enough to squeal from the normal 'running in'. Also the clamping bolt might not have been tightened enough and allowed it to loosen.
The other cause of a squealing belt could be a bad bearing in the alternator - but that is rare. Bad alternator bearings will often fail with no warning noises at all. If you loosen the belt enough to get it off the alternater pulley, you should be able to spin the alternator pulley and have it turn silently and with no movement side to side.

well first of all before all this happen...my timeing belt broke and i had it replaced ..along with all the other belts...in canada here the snow is thick az hell and couple of times i went off the road and hit the snow banks...what im thinking is maybe snow got caught up underneath and cause the belt to loosen up....when i drive at night and use the lights or turn on the vents ..thats when the noise starts to sound.

anyways ..problem fixed..it needed to be tighten ..no more sound..thankx