a/c troubles
 

Hi, this is my first post on site, I have a 2004 durango that we have had since 2006, great truck, 4.7, 2wd slt. The problem is the a/c unit started blowing 65 degree air from the a/c. Front and back. We took it to our regular repair shop and they said it needs rebuilt and priced it out just under 1k$. We said thanks but no and took it home. They did do a evacuate recharge and got the same results, 65degree air and charged me 90$.. The told me it needed a new compressor.

So I replaced: compressor, two expansion valves, and condenser, I flushed the remaining lines, hoses and evaporators. Put it all together and put it under a vacuum for an hour, and let it set for two hours and it held. So I recharged it with the recommended pag 46 oil and freon r-134a 2.5lbs, and still get 65 degree air. This frustrated me and I took it back to the shop, where they evacuated it, pulled vacuum and recharged it, thinking I had made a mistake. The air temp is still only 65 degrees, now I live in the high desert, and it was 98 degrees when I did all this work.

My pressures gauges are reading right on the recommended pressures, around 40-50 on low, and varies depending on air temp, from 220-300 on high side. I did check the rear heater to see if the "flapper door" was stuck, I pinched off the two heater hoses going to the rear unit, and drove it around over 30 minutes, and stopped to check, the rear heater core was pretty cool, and the a/c was blowing 65 degrees, so that eliminated the flapper not working. Front and back has been blowing the same temp, 65 degrees since this all started.

Am I missing something? This is my first a/c job to be honest. But after saying that, my mechanics have said that they can't see what is wrong?

Any advice would be very appreciated!

If you read all my other posts you will see that I have spent 3000.00 on my ac. There was one point where it wouldn't get lower than about 60 degrees. It finally got to where the compressor wouldn't come on and it was fixed today, supposedly, by a dealer. They said it was the high pressure switch. So maybe that's you problem as well.

Greetings bald347, Thanks for the input, and I have been looking at all your post's! Lots of data, I hope your hi pressure switch solves your nightmare. Let us know. I am thinking that something has to be controlling the compressor, because it just doesn't seem to get enough cooling into the evap's. I know that there is a hi and low pressure switch. Is there something else controlling it???

Thanks again!

Nope, that's all it really cares about. Although, it would be interesting to see what the circuit looks like..... The high pressure switch isn't all that expensive..... maybe just replace it for giggles?

High pressure switch replacement
 

I have gone through all of the same issues had my compressor flushed replaced flushed, expansion valves all changed. The shop gave up said they were stumped. I only get cold air when it's below 75 or so. I want to try to change the high pressure switch myself my only question is do I have to drain the refrigerant to change it? If that's the case I'm going to bring it to a different shop.

a/c troubles
 

Hi allrustedout,

I would try to wiggle the key while engine is running and a/c is running! See if that allows the temp to get cooler/compressor run longer! So far this has been my fix!

I did find an evaporator temp sensor in my 04 under the dash/front, it has a rubber plug around a couple wires, I was checking this when I had a phone call, and stopped to answer, and noticed that my aftermarket stereo came on in the dash, (the keys were laying on the dash) so hence forth, I started looking at possible a electrical problem rather than an mechanical one. And so the fun began. I stumbled onto the key scenario of course by accident, isn't this how all great things happen? LOL Not really funny.

I start up as usual, I do keep a thermometer in the drivers side middle vent, and start driving. If after 5+- minutes the air doesn't drop below 62 degrees, I wiggle the key, and almost immediately it starts getting colder.

i know that this sounds funny, I wish I had known about this earlier! It's a simple check!
Good luck

My disclaimer is that I am not a mechanic, my durango 4.7 slt has 160k+ on it, and this could be a ecm, pcm or some other type of computer controlled item. But for now, I finally have a/c at about 45 degrees on a day that is 99 degrees outside. I really beleive it is a electrical issue, not mechanical. Replacing all the a/c parts did nothing for me, well except drain funds.

Good luck to all!