alright guys did some research and found nothing so this was my last option...ok my buddy has a 91 si and his heat all of a sudden doesn't work and the blower is not blowing air at all so my first guess was his blower, but after replacing it, that wasn't the problem, also maybe it had something to do with the blower that we got from the junk yard so if so can you guys help me help my buddy out thanks

 

get your hands on a voltmeter and a test light.. if you look there is a plug near the blower motor (blower motor resistor) take your voltmeter and see if you have voltage going to the plug wit the key on, switch on..or take a test light and just see if the fuse is good you can start off there

 

blower motor resistor or broken wires, check the plug on the back of the heater control unit that has six wires coming from it.