I posted this earlier and never got much in the way of constructive advice. Now that I got things working, I thought I would post my positive experience.
I have a 2001 2500 Cummins TD with 6-speed manual. A/C worked last fall, now it does not. About a year ago, A/C was repaired by previous owner (some hoses replaced) and recharged.
Clutch did not engage, indicating low pressure.
I have the manifold guages and an adapter to tap the can of R-134a. I connected it up and the pressure was low and the same on high and low side. I tried to charge with a can of refrigerant and the clutch on the compressor then engaged for very short periods - a few seconds, but it did not seem to want to take a charge.
I tried again later without the guages using one of those short (12") recharge hoses. Did not seem to take much of the charge.
I filled a plastic container with warm tap water and stuck the can in that. It took the charge. Compressor still engaged for very short periods. But now it did seem to be blowing cool air! I figured this problem is beyond me. Of course, most of you said leave this to the professionals...
Called my mechanic. He doesn't do A/C (or diesel work). They recommended someone local. I called him. He said if the compressor engages for very short periods and then disengages, it is too low on refrigerant. He wanted $135 to recharge. Said probably compressor seal is leaking and they don't replace those, you replace the compressor. $400 just for the part. Probably around $600 plus for the job. Probably more. Did not chide me for putting in refrigerant myself.
So I put in most of another can. Now it works. I bought these two cans at Wal-Mart for around $8 each. Guess I'd better carry some spares.
Funny. My 1986 SAAB 900 Turbo I bought in December 1994 from the first owner came with all the service records. No sign of A/C repair. Two years later It blew warm and I had the hoses recrimped and refilled with R-12 for $150. This worked for about another 6 years and then it failed again. I put in (gasp) hydrocarbon substitute, and recharged it again the next year after it blew warm and it is still working!
Is it the Dodge or the R-134a system that is so failure prone? This truck is only 5 years old!
Charles