93 corvette no a/c not working

I have a 93 corvette, a/c worked fine last year but nothing this year, took it to a shop, they recharged it but said the control unit was faulty, replaced with a new gm unit, still nothing, tried jumping the low pressure switch, nothing. The only way to get the compressor to cycle is to run power directly to the clutch. Any ideas on where to start looking?

only thing i can think of is to turn the control unit on, and use a test light to track the circuit until you find the point where power stops flowing.

Sounds like you may have a vacum leak, check under the hood and remove the cover over fuel injection on the left side, passager side, look for a plastic round valve on the intake that has two small lines going into it. This pic with break or have small hole under it. Due to the heat that the engines put out will dry rought. I had the same problem on mine and took out the whole dash looking for the problem until I started looking for small plastic vacum line that where hook up to the blower motor and vents. I hope his work's for you. I do all the work myself on my vette and have learn alot.

I have a 93 corvette, a/c worked fine last year but nothing this year, took it to a shop, they recharged it but said the control unit was faulty, replaced with a new gm unit, still nothing, tried jumping the low pressure switch, nothing. The only way to get the compressor to cycle is to run power directly to the clutch. Any ideas on where to start looking?

Check the A/C relay and the socket it plugs into. Usually you can swap the A/C with a fuel pump relay to test them. I had a similar problem on my daughter's Pontiac, it was a broken contact on the relay socket.