hi, i have a couple hvac problems. this is on a 96 firebird. 1st issue - the hvac position switch/dial is all screwed up. i am talking about the switch on the hvac controls that control where the air will come from. its completely reversed on mine. i have to turn it all the way to the last mark (suppose to be defroster) for max ac. i put it on max ac and i get defrost. the off position is still off but everything else works in reverse. this problem just randomly started a couple months ago. i hadn't taken anything apart of touched anything. just turned the ac on one day and the defroster was blowing. played around with controls and found out the positions were working in reverse orderform. so, if anyone has ever had this issue and has any ideas, i am listening!

2nd issue - ac stops working after about 20-40 mins. most of my trips are about 40 mins long and air usually stops blowing around the 30 min mark. it completely stops blowing air period. i will not blow from anywhere in the car. i have read where sometimes air will stop from the dash front and only blow from defrost and floor. well, everything stops blowing with mine. its not the blower motor, i can hear the motor still working and have actually taken panel off and viewed motor working. also, i have checked all the vacuum lines and replaced the check valve (even tho the old one looked fine). if i turn the system off for 5-10 mins then back on, it will again blow air. this issue happens regardless if the ac or heater is on, power setting doesn't matter (lowest to highest blower settings), and happens at any positioning location. also, freon level is fine. system is NOT freezing up or anything. compressor and entire ac system is good. this is an issue with vacuum (altho that seems ok) or something inside the dash area, i believe.

hope everyone can understand what i am trying to say. if anyone has any help or advice, i would greatly appreciate it. live in Houston and its getting HOT. already been using ac for most of this yr! THANKS

 

the only thing i can think of for the air not blowing is that your evaporator is icing up and isn't letting any air past it. when you shut it off it melts and works again. check your evaporator box drain for starters. another thing you could drive around making sure your a/c is not on, so leave it set to blow on just your feet, and see if it happens. if you are positive your blower motor is still running, the air has to go somewhere. so you are not getting air to the motor for some reason.