A/C Problem

My Caprice is an 89 with a 305 and the R-12 system. It's been blowing a little warm lately and I've been hearing the compressor kicking on and off, on and off.... so I vacuumed the R-12 out of the system and retroed it to the 134 A. My problem is after I vacuumed it out and started to fill the 134 A the compressor would keep kicking on and off, on and off and now it won't even kick on. The system only took 1 can and is showing full because the compressor won't draw it through the lines. I checked my fuse for th A/C and it's good. Could my problem be with the pressure switch?

Did you first charge it with a can of oil?

I performed the retrofit on mine as well and went through the same problem. Ultimately, setting the A/C to MAX and revving the engine up to about 2500 kicked it on again. Fully charged, it will take about 2-1/2 cans of R134a along with an oil charge.

The cans of 134 A contain the oil. It was a retro kit.

Okay, one can isnt enough... you need almost three. I've retrofitted 2 caprices and a grand pirx so far. The compressor didnt kick on mine until about midway throu ght second can. It'll read that its going WAY overboard until the compressor kicks on. Once the compressor kicks on the pressure drops. As you're filling it expect the compressor to kick o and off repeatedly until the proper amount of refrigerant is put in.

Note: R134a runs at a lower pressure than R12 does, so its not going to be as cold. To make mine ice cold (literally ICE) I jumped the pressure sensor on the A/C system to trick the compressor to stay on at a slightly lower pressure, and BANG, A/C colder than R-12

Actually, R134a runs at a higher pressure than R12, not a lower pressure.

You can jumper the low pressure switch to make the compressor run constantly while you are filling the system. It's on the dryer. Just take a paper clip and bend it so that you can hit both sides of the switch. The compressor will run. Once you are done putting in the number of cans you need. Hook it back up the way it should be.