hi, I got a 2005 mustang gt. When I run the a/c on it sometimes it will work and sometimes it won't. I have checked the fuses but the a/c still messes up. When the a/c does decide to work it blows cold air. I live in Texas so you can imagine how hot it can get during the day. Even going 70mph with the windows down I still sweet like a pig. Help would be much appreciated.

 

i kind of had the same problem with my 96 mustang. running the heat it would get real cold in the winter and go back to hot then back to cold.....my water pump was leaking through a weep hole on it. also have a mechanic check your freon cuz he said that also was leaking. the freon was in the dash so no real easy fix there except to replace the whole damn thing.

 

Sounds like you are low on freon. Which means you have a leak somewhere in the system. Easiest way to tell is jump the low pressure switch and see if the system runs. If it does, well you know you are low on freon. You can try just adding in some stop leak/freon they sell and if its a small leak it will seal it. I could get way more into detail, but first I would see about jumping that low pressure switch.

 

Freon is a brand and they don't use it anymore. Look at the information under your hood and it will tell you what refrigerant you will need, either R22 or R134A. But yes if you need to charge it (add more) you have a leak somewhere.

 

It's R134a. R12 isn't used anymore (think you meant that and not R22). But so what on calling it Freon. Velcro, Nylon, Kevlar, Teflon, etc. are brand names (actual all by DuPont as well) but it's just easier to call by that instead of names like hook-and-loop for Velcro.