Hey guys, I'm having some problems with my HVAC I've started to notice my AC hasn't been working to well only when accelerating when i am stopped in the city it blows hot air. I am pretty sure it just needs to be re-charged but just recently it has been starting to hiss.. same with the hissing when i accelerate the hissing almost goes away. Ive read somewhere that it may actually be the HVAC controls air leaking through one of the 3 *****? is this true or does some one else know whats going on?

 

Sounds like you have two problems; one being the AC is low on R134a and two, the HVAC controls or one of actuators has a vacuum leak.

For the AC, is the compressor short-cycling? If so, then time to take to a shop and have the system checked for leaks and recharged.

For the HVAC: Suggest taking a good look at the vacuum hoses under the hood, especially left upper corner by brake master. Check all the hoses; if any of them feel spongy or leave a black residue on your hand, replace. Actually I would replace all of them...just buy 10 feet or so of the correct size and replace one at a time.

Going to have to spend some quality time under the dash to find the vacuum leak in the HVAC system. May have to pull the HVAC control panel out of the dash and apply a test vacuum to the inlet to test the rotary switch. There are four(?) vacuum actuators under the dash; two above the accelerator pedal and then two behind the glove or storage compartment. The door drops down to provide access to these.

Have fun....good luck.