I replaced the compressor last spring. It's blowing ice-cold and has been a lifesaver.

However, I've noticed after being on for a while, air from the vents stops blowing. The blower works fine on all speeds but won't push any air out. I can shut it off for a bit, cut it back on and it's fine for a while before the same thing starts happening..

Is it freezing up somewhere?

 

My guess is when you loose the air at the vents it is going to the windshield vent. Which that is a sign of low vacuum to your lines. The vent doors work off of vacuum supplied by the engine. You may have a loose or cracked hose or a bad check valve.

 

Thanks Crazy but all my vent doors are working properly. I did some research and it may be my evaporator freezing up due to a bad evap switch (?) Ice may be building up around the evaporator.

If I turn the a/c off for a few minutes (to let the ice melt (?)) turn it back on....it works fine.

 

You can verify that by looking at the drip hose under the truck. If the air flow slows down dramatically and you don't see any water dripping from the hose then the evaporator is froze. Turn off the air, wait a minute and see if water starts to drain out real quickly as the ice melts.

 

The evaporator can "freeze up" under normal conditions. When the air slows down it is just the system trying to defrost itself Id imagine.

 

if it freezes then it stops. it can't blow through ice. the system in these trucks is not smart enough to thaw itself out. your low pressure switch is hanging and the ac compressor keeps running. leaving the blower on with no airflow will cook the resistor so don't try to thaw it that way. the switch has a shrader valve under it so it will just unscrew and screw on. the switch is located on the reciever/dryer (big can looking thing at firewall on right side)

 

Yeah, I spoke to my mechanic guy, he said the same thing. Been too busy lately to really get to it....meanwhile, I'm turning the thermostat up and running the fan a little higher like he also said until I change the switch....which I plan on doing Sun. or Mon. It hasn't froze up with that method yet.

I put a new compressor on it last spring. It'll freeze ya outta there.