PDanner 2003 RAM 2500 AC freezes up

[PDanner]

After driving 30 minutes or more the evaporator freezes up and the air flow stops. Turning off the AC and the fan on high the unit defrosts and the air again flows. Took it to a shop and they said it was the ETR valve and the parts will be $100 and the labor will be $600. Any comments will be appreciated.

 

[SRadke]

There is a sensor that monitors the temp of the evaporator and tells the compressor when to cycle. What they call it I have no idea. Does it freeze up if you leave the temp turned down a bit? (closer to the warm side?)

 

[Pawpaw]

Your refrigerant level is low. These trucks are/were notorious for that when new.



Get one of those refrigerant cans with the hose & gauge. Add refrigerant until it's at the top of the safe zone on the gauge and it won't freeze up any more.



Get ready for posts from people telling you why my suggestion is a bad idea. All I know is that I did it 5 years ago and my AC still works fine.



Bob

 

[BHanna]

Adding a little refrigerant may fix it but probably just temporarily. Most likely you have a leak.

My truck seems to have a problem with a schrader valve that wants to vibrate loose every couple years and it leaks a little refrigerant giving me the same problem. You could check to make sure your valves are tight with a tool that looks pretty much the same as the one you'd use to install a tire valve core. If you find one that's loose, it's probably leaking. Tighten it up and then add some refrigerant.

Of course if the tech checked your pressures and they were ok, he may be right about the sensor but I wouldn't put it past some people to take 10 minutes to fix your truck and charge you $700 for something they didn't even do.