blazer always blowing out hot air

I drive a 1998 blazer and after I replaced the alternator it is blowing hot air out of the vents even when they are not on.  Last night after driving about 65 miles the dash and radio panel was very hot to the touch.  There is also a squeaking noise that started when I would turn the wheel and now is everytime I go over a bump or turn the wheel.

Any suggestions?

Thanks for your help

does the squeaking sound like its comeing from the suspension or the engine compartment? mine has a bad ball joint i think and i only hear it when i hit a speed bump.