$ONE THOUSAND SIX HUNDRED DOLLAR$ TO REPLACE THE COMPRESSOR/!?!?!?!?!

I would RUN away from that shop. I'll tell you what, I will do the job for only $1550.

It could be as simple as the air gap in the clutch not right or it could be the climate control unit. Since these people have not considered such possibilities and instead want to start throwing parts at the problem at a minimum of twice the going rate, you need to find another shop.

ALWAYS be leary of a shop that wants to troubleshoot by just replacing parts.

My $0.02,