My air normally blows cold air but recently it started not blowing hardly at all. It will start blowing just fine but after about an hour in very hot weather the air hardly comes out the vents. It's like all of the vents got plugged. What air is coming out is cold and I can hear the fan still running.
After shutting down for a while everything starts working normally but the problem returns.

Any ideas?

Thanks.

 

Does it only do when you have the A/C on and not when just running with vents. Sounds like the evaporator is freezing up.

 

Been too hot too drive without A/C on but I will try it.
What causes the evaporator to freeze up? Low freon?

Thanks.

 

I am not a machanic and never had a freeze up on the truck. I had one on the home furnace which happen when the fan would not start up. Instead of running with vent only in your hot weather just change the hot/cold selector when it starts blowing slow to hot. That will move the blend door to route through the heater core if it start blowing harder then you know when are getting some sort of blockage in through the evaporator core.

 

Good chance the recirc air door broke off and is laying on top of the blower suction. Its located behind the glove box. easiest way to check is to remove three bolts that hold blower motor in, reach up inside and see if door is detached. If it is, remove it. At some point it will need to be replaced, but it runs ok without it too, if in fact, that is the problem.

 

That wouldn't explain why it works at first, then fades to nothing. Freezing would explain this. If you can, look behind the glove box for a small, two wire, clear electrical plug. It's rather long (the plug..). That connects to a thermometer that is jammed into the evaporator core.

Here's the location of the plug





Verify it's connected properly.

 

Thanks, guys.

BTW, I drove it yesterday with the fan on HIGH and on RECIR and it blew cold air and worked fine. The problem seems to appear erratically. Could be hard to find.

I'm gonna try all of your recommendations and see if I can find anything.

 

This is what I found today. While driving with fan on high and RECIR, the air volume suddenly dropped off to near nothing. I kept the fan on high and just turned off the AC. In about 30 seconds the air volume was back to normal and blowing COLD air. In another minute the air started warming up so I turned the AC back on. It worked fine for hours after that.
What the heck is going on?

 

I had that problem in my chevy that i had and it was so cold it was freezing inside the blower box. When I turned the ac off it was the same way. I just turned the cold to hot for a few minutes every time I did it worked fine for hours. When it started to slow down I just adjusted the heat. But when I ran it on normal ac with out recirculation, it didn't freeze up but on steaming hot days you need the recirculation on imo. hope this helps .