The Expedition's AC is full charged and no links, but when you put the AC on it blow heat as if the heater was on. Now warm air but hot air like the heater is on. If you can help. Thanks
This is potentially very damaging to the compressor so get it fixed before trying to run A/C. What's probably happening is the condenser fan is not coming on due to being broken, bad relay, etc. That's easy to check for yourself, it's in the same area and looks the same as the radiator fan. It should come on and off when you turn on and off with A/C switch. You might also notice that A/C gets cool when you are driving fast but heats up when waiting at a red light. The reason it hurts the compressor is a little complex but here goes - The condenser is supposed to convert the refrigerant from hot, high-pressure gas to liquid so it can be evaporated into gas later in another heat exchanger inside the dash. If the condenser is overheated due to lack of a working fan on it, then the refrigerant stay as gas and passes through the orifice tube at lower pressure, but still a hot gas. This stuff hits the relatively cooler coils in the evaporator and takes the opportunity to condense instead. Condensation throws a lot of heat (latent heat of phase change) into the air blowing out in your face, and sends still-hot liquid into the compressor. Compressors like to see gas coming in because they like to compress stuff. Liquid is not compressible like gas, so the little fins that press the gas together get damaged when they try to compress the liquid. Also, the heat not shed in the condenser is going to increase the heat load on the compressor, which is really what kills it. This will eventually (if not already) send out small metal particles through the system requiring the compressor and a few other parts to be replaced or cleaned out. Since you have an O-tube system there's no other A/C reason for the hot air to be produced. So if you confirm the condenser fan is OK, then you have an electrical/computer issue with the heater controls.
