Looking at wiring diagrams , using A DMM- digital multi-meter an testing the electrical circuit's is the way to find the problem . Because without testing anything said on here would just be guessing . Someone mite get lucky suggesting something to replace, this or that . You could replace a bunch of parts too , before fixing the problem. There is a relay in the electrical circuit that egages the compressor clutch on command from the PCM/ECM -engine computer . Windshield wipers problem could be a simple loose connection ,ground or voltage . Or the motor could be getting ready to go out all together .
Free wiring diagrams here http://www.bbbind.com/free_tsb.html
Enter vehicle info. year , make , model an engine size . Under system click on HVAC ,then under subsystem click on HVAC controls . Click search button then the first blue link . Shows fuse's ,relay ,A/C pressure switch , evap. temp sensor . All these have to be right or the computer will not turn on the compressor . The computer would also have to see a command from the HVAC control head . Alot has to happen before the computer will turn on the A/C .
Electric Testing Techniques You Need to Know
The Trainer 40 When the compressor won compress