Evaporation thermo switch

How do i by-pass the Evapo. thermo switch on a '90 legacy? -- I only want to do it temporarly because I am trying to track down a A/C problem... my switch has three wires coming out of it, which ones do I put a jumper bettween? Everything in my A/C system checks out good, good pressure, all relays are good, all fuses good, compressor is good--- the only things I have yet to test are the evaporation themo switch and the A/C controls themselfs....