no ac after awhile

[lduhrkopp]

A. C. works great but after driving at 70 mph. for 2 hours or so air doesn,t blow out of ducts well. Shut down for a pit stop and ac works fine again.

 

[tgordon]

Soudns to me like you are having fan problems? If it resets after shut down check you fuse panel, it may have a breaker. It is odd, but we had a tractor that the compressor clutch went out on and the HVAC system would only work for a 1/2 to 1 hr before you would loose everthing because the clutch shorting out would trip the breaker.



Troy

 

[Hoefler]

It is freezing up on you. When you stop, it thaws out. I remember something about a TSB relocating the probe in the evaporator to prevent it from happening.

 

[Pawpaw]

Yup. It's freezing up because it's low on R-143.



Someone is bound to chime in to tell us all the reasons not to do it, but I fixed mine by adding a one can to the system. Took a few minutes and less than $20 to by the refrigerant & hose with gauge.



Bob

 

[trqmnstr]

Mine does the same thing. It has the correct level of R-134. Should I add even more?

 

[Crunch]

It is freezing up on you. When you stop, it thaws out. I remember something about a TSB relocating the probe in the evaporator to prevent it from happening.

I had the same problem, and recently had it fixed, just by the skin of the teeth of my 85K/$100 deductible warranty. I first took it in for standard AC service. I think it was just slightly low. I thought that would take care of the problem, but it didn't. I took it back and even though I was 300 miles over the warranty (took a long road trip after the AC service) they agreed to fix the problem under warranty. Right off the bat the service manager told me they would have to replace the evaporator. Took most of the day, but I did get the truck back the same day. Haven't had any problems since. But... when running on fresh air the temp still climbs from just under 50* to right at 60* when stopped at a light. On recirc I get a solid 40* driving and just under 50* sitting at a light. I think my AC is working fine, but the crap they pass off as freon these days is simply being pushed beyond it's capacity for cooling. I remember those old tuna boat cars of the 60s and 70s practically freezing us in all conditions. Hopefully you still have warranty coverage, as this sounds like an expensive repair. They had to take out part of the dash to do it. I wouldn't add more freon than is recommended. I've heard that's harder on the AC system than having it a bit low.

 

[MMeier]

I had the same problem, and recently had it fixed, just by the skin of the teeth of my 85K/$100 deductible warranty. I first took it in for standard AC service. I think it was just slightly low. I thought that would take care of the problem, but it didn't. I took it back and even though I was 300 miles over the warranty (took a long road trip after the AC service) they agreed to fix the problem under warranty. Right off the bat the service manager told me they would have to replace the evaporator. Took most of the day, but I did get the truck back the same day. Haven't had any problems since. But... when running on fresh air the temp still climbs from just under 50* to right at 60* when stopped at a light. On recirc I get a solid 40* driving and just under 50* sitting at a light. I think my AC is working fine, but the crap they pass off as freon these days is simply being pushed beyond it's capacity for cooling. I remember those old tuna boat cars of the 60s and 70s practically freezing us in all conditions. Hopefully you still have warranty coverage, as this sounds like an expensive repair. They had to take out part of the dash to do it. I wouldn't add more freon than is recommended. I've heard that's harder on the AC system than having it a bit low.

Did you have them fix the POS blend doors and such while they were at it?

 

[Crunch]

Did you have them fix the POS blend doors and such while they were at it?

No. I wasn't aware of that being a problem at the time. I've had an above average experience with the dealer where I bought the truck, so I'm hoping they looked at everything relating to the symptoms I described when I took it in for repair. They're a 5-star dealer, and I'm gambling on them not wanting the vehicle coming back for the same repair twice and risking a bad score on their survey (which I haven't received yet, even though it's been a couple of months and they've left messages on my answering maching about how important it is to send back). I don't ride in the passenger seat much, but no one has ever complained about the air being warmer coming out of the right vent than the other vents.