No air from dash registers

[J.V.]

I got caught in a rain just out of San Antonio Monday. Just before the rain, it was 95 and the AC was working so good I had to raise the driver adjustment as I was cold. During the rain I had to switch to the next highest setting on AC control to turn on defrost. After rain, I could get no air out of registers and cab got warm. When I got stopped, I killed engine and let the fan blow. Lots of water started running out of the AC drain an soon air started blowing. Anyone had problems with the coils freezing up and stopping air flow?

 

[GHinton]

J. V. , I have had a similar problem with my a/c and taken in to the dealer once, said they could not find a problem. Of course, I could not duplicate the problem on that day. A/C registers act like they have a valve closed on them, and the blower makes noise like it is on max. Only happens on humid days and after about 30-45 minutes run time on my truck. I will be taking to dealer again sometime soon and let you know if a solution is found. -jay

 

[sag2]

I believe there is an evaporator temp sensor that tells the A/C if the coils are freezing. I will check the service manual when I get a chance and post again.

 

[sag2]

There is a fin sensor in the evaporator to tell the control head if the evaporator is freezing up. The service manual also states under the conditions you were driving in, the system should have been in recirc to reduce the heat and humidity load on the A/C system.

Sounds like you might just want to run in recirc under those conditions and see what happens before you take it in for a possible repair. I know from the way mine works, you could make ice cubes in a real hurry!

 

[GHinton]

Thanks for the info, Sag2, froze up this weekend @ 74* outside temp and about 95% humidity. Should recirc stay on the entire time? Dealer suggests switching over to non-recirc after truck has cooled inside.

 

[RMcCulloch]

Originally posted by GHinton

Thanks for the info, Sag2, froze up this weekend @ 74* outside temp and about 95% humidity. Should recirc stay on the entire time? Dealer suggests switching over to non-recirc after truck has cooled inside.

One "good" reason to switch off the recirc occasionally is to avoid turning into an icecicle.



Seriously, though, mine stays on recirc 95% of the time that the engine's running and I've had no problems.



When the temperature and humidity are both in the high 90's, I enjoy the cool, dry air coming from this A/C!