I am new to the forum. I have a 1998 Dodge Dakota Sport with a V6. My AC will not cycle. I have had the pressure checked, and it is okay. I have replaced the high and low pressure sensors. I have replaced the clutch relay. On a warm day the AC will run for about 20 minutes and then stops and only blows hot air. When this happens the clutch is disengaged. If I cut the AC completely off for about 20 minutes, it will work again for a short period of time. When I first got the truck, the AC would cycle on and off. It no longer does this. It stays on continually until it freezes up.

What is wrong?

Gene

 

Hi and welcome to the forums. I moved your post into a new thread.

What are the pressures, high and low?

Moisture in the system, if it wasn't properly evacuated, can freeze up. When the pressure gets high it would shut down.

 

I had two different certified a/c companies drain, and inspect the system. They found nothing wrong. I had them replace the low and high pressure sensors. They told me that the pressures were well within range. If I turn the fan on low it fails quicker. The truck cab gets very cold in just a few minutes. It run for about 20 minutes and shuts off. It gets too cold, but does not cycle.

 

Is the drain to your HVAC clear? The humidity from the air collecting on your condenser could be making a pool of water inside your HVAC box, any water pooling by the condenser could be causing your freezing up because the cold condenser is sitting in the water that should be draining into your engine compartment through the firewall behind your engine.

 

You could try removing some Freon out of the system

But check to be sure you don't have water in the box check to be sure its dripping water if not its filling with water and will freeze up

Your dryer may be shot it removes moisture out of the system did they replace it at one of the shops?

Did they remove the A/C Orifice Tube and replace it some Orifice Tubes are meant for high temp conditions like 105 and above maybe they put the wrong one in.

 

I had a very similar problem as well, my truck wasn't staying cold and wasn't cycling. 98DAKAZ is on to something... I removed some freon and now it works awesome. I think when I recharged the system and it was giving my problems I kept adding freon (OOPS). Once I removed a little bit it worked great! I think it was a combination of overcharging and a little moisture in the system.

Is your compressor operating properly? No bearing issues at the clutch or metal shavings between the clutch and compressor??

 

I had an issue like yours last summer. It appears in my case that the A/C clutch was slipping then overheating to the point that it wouldn't turn the compressor anymore. I undid the center nut holding the A/C clutch friction side to the compressor shaft and removed a shim to allow the pull in windings to clamp the clutch in tighter. This was a $0 fix in my case and didn't cause any engagement / disengagement issues. All you will need is a ratchet and socket 10mm as I recall. With the engine off remove the center nut from the A/C clutch. Then take a shim off the compressor shaft from behind the clutch. Replace the parts in order of removal less the shim and test for proper operation. To test to see if the clutch now holds 1: Start your engine in park or neutral and park brake set then turn the A/C / heat selector switch to Max A/C with the cab doors open. The center part of the clutch should be rotating, note any grinding squealing. 2: Then check for disengagement by turning A/C / heat selector switch to off. The center part of the A/C clutch should be stationary and note any grinding squealing. 3: Take for test drive to see if the clutch holds once things get warm. If you get grinding or squealing coming from the clutch or the clutch doesn't disengage when the system should be off put the shim back. I hope you have the same luck I had and get away with an adjustment rather than replacement of the compressor or clutch.