AC dying after 2 hours driving at 70 mph

[agfckrowe]

Help! I drove our 2003 manual transmission 3500 for 3 hours at about 65-70 mph, everything's fine. Then after parking it for an hour, and driving for 2 hours, the AC quits putting out cold air and it seems like the fan is not pushing out the normal volume of air, even on high (its sounds like the fan motor is running on high, just not normal output both in terms of volume and temperature). This happened again one month later, with the same amount of time driving, same highway speeds, both times with outside air temps in the high 80s. When you living in the humid south like I do, I just can't live without AC. The only other post I could find (with a slow dial up PC) referred to the AC not working at an idle, not driving at 70 mph for 3 hours. Before I take it to the dealer, I'd like to have an idea what I'm looking for since our closest dealer is 1 1/2 hours away.

Thanks!

Karen in Arkansas

 

[JCleary]

Supposedly the air conditioner freezes up and will stop blowing cold air for a while. Then the ice melts and it will blow cold again.



Turning it off should melt the ice and let it blow cold again after a few minutes. Fortunately for me it only happens on the passenger side.



There may be a solution, replacing an A/C sensor. If you do a search, someone here has been working with a dealer on a fix.

 

[agfckrowe]

Nope, tried turning it off to let it "thaw out" and that didn't seem to do much, unless the thawing out process is supposed to take several hours, which is hard to take when its in the 90s outside.

Never had this problem with my 99 Dodge diesel automatic 2500, why the heck is this one a problem?

IF I go into the dealer, will his magic computer find the problem, or will I have to pay out of my empty pocket and convince him to replace what may be a perfectly good ac sensor?

Karen

 

[p-Bar]

Do you feel the compressor kicking on ?? check fuse

 

[Boonieman]

Is there water dripping out the bottom of the truck where it normally does when the A/C is running? Sometimes the drain tube can stick closed. If it's actually freezing up, turn off the compressor but not the blower fan. This will force warm air thru the evaporator coils and thaw them out a lot quicker. Again, if it's really froze up as it's thawing you ought to see quite a bit of water running out the drain tube located under the truck forward of the passenger seat in the lower firewall area.

 

[CTD 600]

Tipically the hotter it is outside the quicker the a/c sensor will freeze up or not work. Turning off the a/c to let the water condense will solve the problem. Should not take more than 5 minutes. Also, when the a/c is off, run the air with fresh air from outside to help flush the humid like air that may be in the system. If you don't flush it, the next time you use the a/c there may be a rotten/moldy smell that comes from the system.

 

[DPKetchum]

Sounds like its freezing up. Turn ac off not the blowerr and it should thaw. No COMPUTER will diagnois this. Lots of threads recently on the subject. STAR(D. C. tech helpline is aware)just had a new fin temp sensor and it relocated in a differant section of the evaporator. Have NOT driven mine on a long trip yet to see if repaired.

 

[Jeremiah]

AC freezing up

Same thing happened to me, Karen, a couple of weeks ago. I turned off the compressor (push the button) for about five minutes while leaving the fan blower on. It quickly began blowing cold again. Then, when it began blowing warm air, I turned the compressor back on again. This back and forth went on for a couple of hours. A pain in the butt, but it was better than being hot.



I took it to my dealer who at first said it wasn't covered under my extended warranty. He just didn't know because it is. At any rate, he said whatever they put in air conditioners these days was low. He couldn't find a leak so he did an evacuate and recharge and it's been working fine. He also put some dye in it and wants me to bring it back to see where the "leak" is.



That's the status of mine right now. 55,000 miles on the vehicle.

 

[Elite1]

Mine just did the same thing, for the first time on a 3 hour trip down to San Diego, about 2 hours into it. The fan seemed to quit blowing although the motor was still humming and a little bit of cold air was coming through the vents. I pulled into a gas station and popped the hood, the AC was froze up like a huge ice cube. btw: 59,600 miles on the truck. I would like to know what Dodge's solution is to this problem, is it just in need of a recharge of freon or whatever chemical they use these days?

 

[DPKetchum]

Lots of reports of this. A fin temp sensor and its relocation. Star(D. C. tech help line is aware!)

 

[agfckrowe]

"just had a new fin temp sensor and it relocated in a differant section of the evaporator"

This is a little more technical than I can understand. Was this done at the dealer under warranty? Is this what Dodge advises as a "cure" for this problem?

Thanks,

Karen

 

[scotty1]

I had the same problem.



Dealer found the system to be low as well as needed the doors recalibrated and a new sensor... now it works better then new!



If I could only get my new inejctor pump life would be good.

 

[Elite1]

Scotty, was it a freebie, or did the dealer charge you? If so how much? How many miles on your truck?

 

[NIsaacs]

In high humid conditions, don't use max ac. It uses recirculated inside air and adds to the humidity and freeze up problems. Using outside air may help?





"NICK"

 

[DPKetchum]

Mine froze up last summer and checked/recharged and still froze up. Fin temp sensor is the thermostat of the A. C. system. They relocated it so it would get a differant feed and stop the freezing up. Common repair over the years except the old style you removed the glove box to move it. These are in the heater/evaporator case which requies dash relocation(partial removal). Yes it was under warranty. I never hardly ever use MAX ac exept for a few minutes at any time. Leaving them on MAX or RECIR air for long periods causes nasty odors!

 

[Elite1]

In high humid conditions, don't use max ac. It uses recirculated inside air and adds to the humidity and freeze up problems. Using outside air may help?"NICK"

What is "max ac?"... Mine just has an AC button, on or off. Then it has a fan motor dial, which has 4 settings. I have a seperate switch for recirculate air or fresh and I always leave that on fresh.

 

[DPKetchum]

MAX or RECIR. Same thing. Recooling the same air over and over.

 

[Eric_77]

I have had this problem with several vehicles my solution is leave AC on and turn temp knob to full heat by the time you get warm air coming out of the vent the evaportator is thawed and works normal again. The times I have the most problem with it is summer rain storms (or just after) when we are in the upper 80's and near 100% humidty.



Oh the nasty funk smell if you leave it on recirc/max is sweat/bad breath. my old roomate did a test for GM on this they now equip their Cadillac with a switch that runs fan on low for couple minutes after shut off so that fins are fully dried and smell goes away. I try to do this every couple days when it is cool in the morning (run vent only to dry system completly).

 

[Jeremiah]

Ac quitting cooling

Took the truck back to the dealer today after two weeks of running it on a recharge. Dealer service writer says dye indicates nothing escaped from the system. He also said the fin thing wasn't a problem in my truck, that it had been fixed the last time it was in. We'll see.

 

[Patriot_RAM]

More info?

Hey Guys,



It must be something about Arkansas because I'm having the same problem as Karen. I just drove from the north part of the state straight south for a couple hundred miles. After about 75 miles, my a/c stopped working right. It was still blowing cold air, but the volume on high was less than what the normal setting would blow.



You guys are saying that it's freezing up -- What exactly freezes? Does it restrict the actual airflow? I've been at my destination for 20 minutes and just went out and turn the key on in case something had been frozen up. The airflow is still minimal. Any suggestions? This just started happening today.



Thanks!