idle surge when A/C is on and blowing hot air

[Chris B.]

Okay, so it's starting to get hot here in Phoenix so I decide to turn on my air today and it starts blowing hot air and I'm getting an idle surge when idling. Anybody have any ideas on what might be going on? I was using the air a little bit last week and it was working fine. The idle surge is bumping between 500 and 1000 rpm.

Any ideas would be greatly appreciated!!

[Jacostang]

Sounds like it trying to cycle itself, sometimes the ignition switch is a lttle too far foreward, the switch controls the electric and engages the ac. When the ac engages it idles higher so it might be right on the edge, this is common on fox bodies too..

[Chris B.]

Any ideas on how to fix it?

[Jacostang]

The best way is to replace the swtich bvut I never did on any of my other cars just turned the tumbler back a bit and it engaged...Still does it some times on my 87, I forget and wonder why the ac isn't comming on then Duh I remember and just jiggle it and goes away.

[Meatwad_03GT]

Prob just low on refrigerent. My old 99 used to do the same thing when it got low.

[Arch Angel]

Exactly. This is pressure regulated to protect your compressor when its low on refrigerant. When I charge systems, I'm looking for leak indecators at the ports and line connections for visable oily film. These can leak also in less visable areas such as the coils and front seal on the compressor. A simple charge may be fine for the year. If your system becomes comletly dry your a/c will not come on at all.