Speaking of auto A/C 94 Caravan Compressor cycling

DieselPower · Aug 24, 2007

To help you out I would need to know the low and high side preassures along with the ambient air temp and approximate humidity level. After you find out your pressures I can help you diagnose it from there. I would really be curious to hear what the "a little high" high pressure is. It sounds like a partially blocked expanssion valve that is causing high pressure, the high pressure switch is doing it's job and cuts out the compressor, pressure drops and the cycle starts all over again.

irwin · Aug 24, 2007

DieselPower said:
To help you out I would need to know the low and high side preassures along with the ambient air temp and approximate humidity level. After you find out your pressures I can help you diagnose it from there. I would really be curious to hear what the "a little high" high pressure is. It sounds like a partially blocked expanssion valve that is causing high pressure, the high pressure switch is doing it's job and cuts out the compressor, pressure drops and the cycle starts all over again.

I'm thinking along this line also, would like to know how you know it's full, did it get evac'd and vacuum applied? how many ounces R134a is in there? Not doubting you, just curious. AC systems for a 94 caravan are fairly straight forward.

Soundguy · Aug 25, 2007

Seems we have all been asking from the beginning what his high pressure is...

Soundguy

BobReeves · Aug 26, 2007

Have to admit when Tom had the gauges on I wasn't paying allot of attention to the actual pressure readings, left it up to Tom's expertise as a 20 year retired auto mechanic in a GM dealership. I had over filled it before I took it over to Tom's place, he used a chart, a digital thermometer and his gauges to set the charge where it was suppose to be. We bypassed the compressor relay to keep the compressor running so he could make sure the charge was good. I did notice the thermometer he stuck in an air vent was reading around 50 deg with the compressor running.

I never have normal problems with anything, it's always something weird that nobody has ever ran into before. We think the computer is telling it to cycle but can't figure out why. My thought is another sensor that might not normally have anything to do with the AC is acting up. Am sure this isn't right but for example if the computer thought the engine was over heating it might turn off the AC..

I'm thinking about running a couple wires to the dash and putting in a bypass switch, let that sucker run till something blows up

Soundguy · Aug 27, 2007

Just for kicks.. have you had a scan done to look for embeded error or fault codes in the ecm?

Soundguy

BobReeves · Aug 27, 2007

Soundguy said:
Just for kicks.. have you had a scan done to look for embeded error or fault codes in the ecm?

Soundguy

No but what a great idea, I'm still stuck in the 60's before cars had computers.. Thanks will check it out...

Read the codes and from what I can tell from what I found on goggle it didn't tell me anything I didn't already know..

12 - Battery or Computer disconnected
33 - AC clutch disconnected..

Both of these were probably done when we were troubleshooting the AC system so I can't see where they are any help. The switch is sounding better all the time