[davidpc]

When I sit at idle, or go less than 15 mph, the air conditioner works great. But if I get up to 20 or above, it quits working and blows hot like I turned the A/C switch off. I have changed batteries recently. It did it before and after. So bu changing the battery, it should have reset the ECM if there was a problem there. And the battery was out for about 2 hours as I pulled it then went and bought a new one so I didn't have to go back for the core charge.

Any ideas? Getting warmer

 

[Russ Bellinis]

I think you will need a shop. Your system will have high and low pressure cut off sensors. If you are getting either high pressure or low pressure cut offs you need to find out if it is a sensor failure or if you actually have high or low pressure. Some cars are set up for the electrical system to shut off the compressor if the engine is having to work too hard like climbing a mountain. If you just start changing parts, you might get lucky or you might just spend a fortune in new parts that don't fix it. My Magnum was cooling fine for the driver's side, but my wife complained that her side of the car was not getting cold. It turned out that I had leaks at the shrader valves in the suction & discharge ports. If your engine overheats, the computer will possibly chut off the ac to help keep it cool. You could have a freon leak, or moisture in the system. I've probably toalk about lees than 10% of the possible problems. Take it to a shop to have it checked out by a professional.