I am having issues with my a/c. With gauges attached, my low side is reading 34 psi, and the High side is never exceding 160 psi. As long as i run a water hose on the condenser, the clutch will cycle normally and blow ice cold air. But as soon as i take the water off, after the condenser heats back up, the clutch will cut off and not come back on. When the compressor quits the low side goes out of range "high" , and high side never climbs above 160. What is kicking the compressor out. The bottom two tubes in the condensor are blocked by bent fins but the rest of the condenser is clean as well as the radiator and the intercooler as well. Any help woud be apprecieated.

 

i'd suspect you high side guage is defective. hook the gauges up before you start the engine in the cool of the morning and see if they are reading the same pressures.

There is a high pressure cutout also that might be defective.

Also are you running the test at idle or around 1500rpm?

 

1500 to 2000, it was late at night last time i checked it. Is the high pressure cutout right by the compressor. If so does it have to be changed with the system empty? The pressures were 37 and 180

 

Also have you heard of using hotshot "414b" instead of 134a. After a complete vacuum, I put it in my z71, with 134a oil, and it maintains bout 41 degrees in 100 degree heat. Pressures are 27 and 240

 

You might be too low. I just had an issue with my a/c system with rapid cycling. My low side switch was cutting out at 35psi. I found the dealers manual online and posted it here in forum. It does have a chart that you have to use. I'll pull in the chart for ya. Most of you will be pretty surprised where the pressures should be. But my a/c fogs up windows now. But once you have confirmed your pressures are as close as you can get them, then we can start trouble shooting. Keep in mind that the high and low side can vary big time because of the ambient air temps in the cab and outside. Keep this in mind because if your truck has been baking in the sun all day, your pressure will be through the roof and all over the place. Once the cab starts cooling down and the truck warms up and kicks the cooling fan in, you will be able to get a more proper reading.



Hope this helps!

Woops! Sorry it's so small, I found the download link for the manual. Here ya go! http://www.rm-indy.com/wavefiles/2001ramsrvcmanual.zip

Ps: Your high side may be low because your cooling it down with water, the cooler the condenser is, the lower the pressure is going to drop. But it could be a defective gauge as well like bgflatbed said.

 

The pressure should climb up past what is is when its being cooled with water. If it doesnt , i would assume the gauge is faulty. My guess is that you dont have proper airflow through the condensor and thh hotter the condensor is , the higher the pressure will be and might be spiking on the high side and cutting out the clutch. Check fan clutch as well as restricted air flow between rad and intercooler.

 

With the system and engine turned off, both high and low pressure should be at the current outside temperature. (IE: 90 out side, pressure should be 90. 70 degrees, both should be 70). Or at least very close to the OAT. Any thing different then that, you have a problem from the get-go. The "Low Pressure Cut Out Switch" is designed to keep the compresser from eating itself up from lack of pressure on the high side. If you had a large differential pressure with the system static, you have gage problems. Or hoses collipsed internally. Temperature of the condenser is not a factor, PRESSURE IS A FACTOR. It is what causes the clutch to kick in and out. You could also have a bad clutch as well as a pluged expansion valve and dirty receaver/dryer or a bad high or low pressure switch. All things are possable. Sort of hard to troubleshoot. I would start with the hoses and gages. (KISS) Keep It Super Simple for me.
Just my $.02 worth. Hope this helps.