Air conditioning problem

[Spice137]

I have a 99 Ram 360 and the air conditioning doesn't work. I bought a recharg kit thinking that it was low, but when I hooked it up the pressure read 45psi. Actually, with the air conditioning turned on, the compressor intermittetly turns off and on. When it goes on, the pressure is at 45 and then goes to 0 when the compressor goes off. I felt the two refrigerator pipes that lead to the inside of the cab and found that the lower pipe is cold, but the upper one is not. Does anyone know what the problem may be? Is the compressor suppose to be on all the time when the air is on, or does it go intermittetly? Thanks for any info.

[fredjacksonsan]

Sounds like it is a problem up under the dash, either with the heat exchanger or vent controls. Since the lower hose is cold, the refrigeration part of the system is working, but that cold air isn't getting into the cab. I'm not an underdash guy so that's about as far as I can help.

[dirty dan]

Originally Posted by Spice137

I have a 99 Ram 360 and the air conditioning doesn't work. I bought a recharg kit thinking that it was low, but when I hooked it up the pressure read 45psi. Actually, with the air conditioning turned on, the compressor intermittetly turns off and on. When it goes on, the pressure is at 45 and then goes to 0 when the compressor goes off. I felt the two refrigerator pipes that lead to the inside of the cab and found that the lower pipe is cold, but the upper one is not. Does anyone know what the problem may be? Is the compressor suppose to be on all the time when the air is on, or does it go intermittetly? Thanks for any info.

Sounds like you're low on R-134.
A system at rest should show around 80-100 psi. Low side on run shouldn't drop down to zero. It should probably get no lower than 30 psi. Sensor is seeing low pressure and shutting off your compressor. It keeps from ruining your compressor. Trick will be to find where the R-134 leaked out. Likely culprit on a Dodge is evaporator core.

Go to doityourself.com, In the auto forums you'll get good advice on your trucks A/C system.

[fredjacksonsan]

Thanks Dan, I wasn't sure of the pressure.