[quickywd01]

I was servicing all of my friends cars a/c systems and since his caddy had no r-12 in it I put a retrofit kit on it and tried to start filling the system. When he turned the a/c on the compressor kicked on and the r-134a can got cold then the compressor turned off after a few seconds and it never turned back on. I tried jumping it to keep the compressor on non-stop but it didn't seem to respond. What should I check out? Could it be a relay or something?