So I have a 96 Blazer, 2wd 4.3L V6 that I decided to put a Performance Accessories 2" body lift on. Well for some reason, ever since I put the lift on, my ac compressor wont really engage when the ac is on, but the heat will work, if by chance the ac compressor does decide to kick on when i put the ac on, i wont be able to use the heat if i turn the thermostat over. Sometimes, neither works, it's just like normal air is being blown through my vents. Prior to the lift everything worked perfectly. I have no clue what happened or why it's doing this but it's highly irritating. Please help!

 

Have you checked your blend-door actuator? (should be behind the glove box). if this is bad, I find it unlikely it had anything to do with a body-lift...just coincidental.