My A/C blows warm and I occasionally get the little notebook code on the display of my 99 RR. Last week I inspected all fuses and even swaped a few relays to try and get the compressor clutch to engage. No Luck there. Today I verrified the the refrigerant level was correct and the clutch still did not engage. I have tested for power at the compressor - 0v. I ohmed the connector to ground and had good continuity. I started visually inspecting the system and did find the sensor on top of the Drier was unpluged. I pluged it in and still no engagement. I unpluged the sensor in the high side line next to the drier and jumped the two terminals together in hopes it would work, Nothing. I am pretty sure my outside air temp sensor is working correctly cause it has always been pretty accurate with the temp. I am also pretty sure the inside temp sensor works as I was able to get the fans to change speeds using the cigar lighter test. I did jump power and ground to the compressor and it will engage and blow cold air. So what is preventing my compressor from engaging when I have the A/C on?

I am guessing a controller issue or a pressure switch issue.

Any Thoughts?

 

thread is continued here:

http://www.lrrforums.com/showthread.php?t=7141

 

Im having the exact same problem on my 96 4.0. New trinary valve, charged system, and nothing, only hot air. When i run a 12v direct to the compressor, it is ice cold......?????????