pickup a/c quit, or did it?

[Kelly in tx]

I hauled my tractor back from dealer repair Friday. It was about 80 miles. I have a 25' bumper pull trailer and pull it with my Dodge 3500 Cummins diesel. The engine temperature was pretty normal (always reads about 205???). By the time I reached home the a/c was no longer blowing cold. After arriving and unloading and unhitching, I showered and changed clothes and left in the pickup again. The a/c worked fine. In fact over several uses the a/c has worked fine. What's going on?

 

[Janicholson]

The humidity probably iced up the evaporator and stopped the transfer of cold air. Make sure the drain hose and little rubber nozzle (if it has one) are not plugged up. (

 

[used red MN]

The A/C evaporator in the dash would be more susceptible to freeze up if you run it on “recirc” continuously.

 

[NDIHC]

A system that is slightly low on charge can have low side pressure that is roo low, which will result in colder than mormal evaporator temperature. Sounds counter intuitive but true. If the refrigerant level gets any lower it likely won't cool, but there is a point that a SLIGHT undercharge can cause evaporator freezing resulting in no cooling until the ice melts. Also, a restricted cabin air filter can reduce airflow and allow an evaporator to freeze.

 

[cumminstinkerer]

Just fixed a 95 Ford 7.3 saturday that was doing the exact same, it was a smidge low on gas, I guess 29 years was the limit, the wifes 05 Dodge diesel did the same when I replaced the transmission, I undershot the charge, did an evac and vac when I replaced the evaporator and fixed the blend doors, charged it by weight and all is good, that is the best method, total recovery/evac, vac then charge by weight to sticker spec!