The A/C in my Jeep works great at idle and probably any speed below about 35mph but once I get going, it seems like the compressor doesn't cycle back on.

Any idea what's going on?

 

Check your vacuum lines, maybe you are loosing it when the throttle is open due to a leak. Maybe your blend door is acting up when it looses vacuum and it just seems like it's not working? Are you positive the compressor isn't cycling at highway speed, maybe the belts slipping.

 

is the air temp changing or the air flow

 

The air temp changes.

I'm not sure if the compressor is coming on or not. It just feels (the air) like it does not.

I don't think it's the blend door because the A/C does not start working again when I slow back down. The truck usually has to be off for a little while for it to start working again. Simply turning the air off and back on a few minutes later does not make it work.

Also, it does not seem to have to do with revs. I can wind it out in the first few gears and no problems.

It may be a time thing and it just seems like it has to do with speed. But ... why would the A/C stop after a few minutes and then work again after the truck is off a little while?

 

Had a car at work that was doin that and it was over charge on freon so it was shutting down the compressor.

 

How'd you fix that?

 

Before you drain out the system turn it on and have it run at 2000 rpm (approximately the engine speed that you cruise at) and see if you can see frost on the lines after a min or two of running. If it freezes before the h block then there is a blockage in the line and the r12 or 134 a is not transfering the heat out of you xj. Also check the compressor if it cycles too fast or not at all. If it cycles too fast then your overcharged( if your running 134 a) because the jeep is looking at the high side to cycle the compressor. If it stays on all the time you might be low. But from what you stated sounds like it could be slightly overcharged. Make sure you auxiliary fan is running. All else fails start hitting sensors and the h block just in case they are stuck.

 

Got nothin else.....Kelly said it all. And most times the evaporate the whole system. But I'm sure u can let some out and put some freon that's got some lubricants in it to help the system

 

OK. Will check tomorow. I just had the system drained and charged about a week ago. Before that, the A/C was pretty weak. Now it's either freezing or not working.