A/C Troubleshooting

[Devin668]

I have a 93 Bonneville. The AC system will only work if the lower switch by the compressor is jumped dorect to battery (upper switch near dryer is jumped during this test). We are only getting about 60lbs of head pressure after cleaning the system out and putting about 2 cans of 134a in. Anyone have a step by step how to follow the circuit (or any other thoughts)? Thankls for the help. By the way, after recharging the system it will bring temps down from mid 80 deg to mid 50's on low fan.

[richtazz]

The switches are there to disable the compressor if the refrigerant is low to keep it from grenading itself. If you are converting from R-12 to R-134, you need to be sure all the R-12 was evacuated out. If the orifice filter (which is in-line to the condenser) is plugged, it will cause the hi-side pressure to spike, which will trip the hi-side switch to shut the compressor off. If you haven't changed the orifice, that is most likely your problem. Hooking up a set of guages will confirm.