My ac doesn't blow as cold anymore, still cold just not like it used to. I tested the system, ac pressure while the car was idling and ac on was 30 PSI on Low side and 170 PSI on High side... Outside temp was about 75-80 degrees... Also the ac shuts off on the car revs past 2-3000 rpm, the pressure on the high side climbs and when it reaches 300 psi or so the ac shuts off... Are my PSI readings off? How do i fix this?

 

If I had to guess, I'd say it were the Thermal Protector, or the AC Pressure Switch. It shouldn't shut off unless the pressure is above 455psi, though.

It could also be air in the system, clogged condenser or radiator fins, etc.
I'd take it in for an inspection, or purchase a shop manual and do it at home. The troubleshooting (is) can be a bit of a PITA.

 

I have a similar issue my ac will not come on unless I jump the ac condensor relay port. I took it to a mechanic and he told be I had to replace the Ac condensor relay because it was blown.So went to buy one and replaced it.I also replaced another relay I was told had something to do with the ac...But the only way it comes on is when its grounded and jumped other that that nothing>>>>>Help please..

 

The pressure doesn't get to 455, unless my gauges are waaay off... Also is it normal that as the engine revs up the pressure on the high side increasing while the pressure on the low side decreses?

 

Start simple, check fuse number 1 (20 amp) and number 4 (20 amp) in your under-hood fuse box. If they're okay, check fuse number 14 (10 amp) in the under-dash fuse box. It may be that you need to replace that under-hood fuse box, or it possibly has an open wire along the track.

If you're still having trouble with it in a couple days, I'll jot down a more detailed "how to" .. I'm a bit pinched at the moment.

 

To be completely honest, I have no idea. I've never worked on an air conditioning system therefore I do not understand entirely how the system works.



As noted in post #2

 

I just read that as rpm goes up, pressure on the low side is supposed to decrease and pressure on the high side is supposed to increase. I will check the fuses you mentioned and I will also test the compressor cluch relay

 

Tested the fuses under the hood and the one under the dash, all read 12.33 or 12.34 volts on both sides. Fuses are good, also tested the compressor clutch relay and fan relay and both are good. I might head over to a shop to have them test the pressure in the ac system to make sure its not too low or too high...