I have an '04 3500. The A/C works fine most of the time, but sometimes I'll be driving down the road with it on Recirculate and the temp all the way to the left and it will quit blowing cold. Problems also happens if I'm pulling a trailer and wind it up to get to speed. Any ideas?

 

If it starts blowing out the Defroster it is a vacuum problem.

If it stays blowing out of the dash vents, I would say it is low on Freon. I system that is low will freeze up, and stops blowing cold till it thaws out.

Hope this helps, Rodney

 

Don't the newer trucks shut off the AC if your using too much power? pulling a hill with my TT my AC shuts off, no more cold, just air, as soon as I crest the hill it's back to normal cold air. I don't know for sure though. My folks Subaru does the same thing.

Good luck.

 

i have noticed the same thing but only when i have been pulling, also i will see smoke/fog comming out of my vents. Is that i sign of low freon? mine when it messed up i can have the blower on high but it will only blow low out the vent but i can hear the blow working like it is blowing high. and it isn't comming out any other vents....... hope it is somthing small like the freon cause i live in texas and can't go with out A/C

 

As 2500Ram said the computer could be shuting off the A/C to use the power other places. I haven't had this happen in my 2000 and have had it when stock floored pulling hill loaded to 20,000lbs.

Most of the time frost or fog out of the vents is caused by freezing up. Low freon is the most common cause of this. There are a few other thing that can cause it also. A bad high pressure switch, that want let the system cycle off and on. A over charged system can also cause them to freeze up.

Under a hard pull (on the floor) some will loose vacuum and switch to the defrosters (common on gassers). I have a 87 Dodge Dakota that has over 300,000 miles. When on the floor will only blow out the defrosters because the old wore out motor want pull enough vacuum to keep it blowing out the dash.

 

That sounds about right if you are losing only the cold air when stomping on it pulling a load. However, if you cold air cuts out with no load, I'd bet you are low on freon. Since it's a closed system you could also be looking at fixing a leak. If it is the freon and you run your a/c to much with too little of it, you could fry part of your a/c system.

 

The AC in my old F-250 quit working. Took it to the shop and they said that the compressor will die on you if it see's to RPM's. I had gotten stuck in the mud several times before and remembered having the AC on and gassing the rods out of her!!! I now always turn the AC off when it comes down to highers RPM's...

 

WHAT, I doubt that a dodge diesel, turning only 3200rpm would burn up the AC compressor. What could cause it may be all the muddy water that you keep getting into at the teil!

Stephen

 

The problem also happens when I leave a stop light. The fan speed never slows down, and keeps blowing out the vents correctly. The air is just not cold. When it is blowing cold it works really well. Is this a R-134 problem or some type of switching issue.

 

I had similar problems with my 2005-Dodge 3500 and now as of a week ago my system is now stuck with cool air coming out the drivers side and slightly cool air out the passengers side. The evaporator tube that is visable from inside the engine compartment is freezing up so a low charge of refrigerant is not the problem. (The frost is caused from not enough air flow through the evaporator. The problem appears to be a stuck blend door in the back of the HVAC box. There are 5 blend doors, two of which control heat/cold, and the redirection of the air flow to the passenger side. THe blend doors are controled by DC linear motors and can fail in a number of ways. According to the Chrysler manual, this problem cannot be corrected without taking out the entire dash.
I don't want to take my truck to the dealer for typical "dealerization treatment" but would prefer to do it right, (no left over screws, cutting or hacking). Any ideas or help available?

 

Yes, it does sound like you have the blend-air door issue.

It happened to my '05 last August - the fix is to remove the dash

... even though my warranty would cover it, I don't like anyone else handling my trash - besides, they'd take one look at my truck and laugh themselves silly on a warranty claim!