Ac not blowing cold

It's broken. Don't use it .Could be a variety of things. Best to let someone hook up gauges before you do anything. Check low and high side pressure. May just be low on freon....or something much worse.

 

The most likely problem is hot water flowing through the heater because the valve is leaking.

 

Could be the blend door. Is it always hot? Could be low on freon.

 

Lots of could be's. First thing i usually do is shut engine off. Turn on ignition to run position. Then switch on ac, also cab blower motor. As you switch ac on and off listen for the "click" up front. If unit is charged and prepared to pump freon you should be able to hear the electric magnetic clutch engage/ disengage on ac pump as you cycle switch. No click no freon gonna get circulated. Then find out why. Wire off or broke somewhere. Loss of freon. A pressure switch gone bad. I have added freon before with ignition and switches on, as freon goes into system the ac pump will click, which means now its ready. Then i start engine with ac still engaged and continue to fill. I use a guage i purchased at walmart. That informs me how low system is. Works for me to check out this first before i take it to the shop. Hope this makes sense and helps.

 

A little more detail would help. Does it come and go while driving, or just while idling? Is compressor running all the time? Or is it cycling normally, staying on longer than off, at an idle? Or is it short cycling, on and off quickly? Can you turn it off, wait a few minutes, and turn on, start working? Any info might help.

 

With it the AC on. Is one of the AC lines cold in the engine compartment? One of them has to be cold. I would probably go to Walmart and buy a can/charging kit. Hook it up and see your pressure. The AC compressor has to be turning for you to get an accurate number. Then for $25 you can see if it's the amount of Freon or if it's something else.