I came across a Carrier heat pup unit and hig voltage good low voltage was going through the board OK. I took off the yellow leads at the contactor and hooked it up str8 to the stat wire, and the unit kicked on. I went probing around the board with my meter through the back of the plugs and the damn thing kicked on. Probing through the back of the wires going to the board coming from the switch which does not have a screw in adapter. Do I have a loose connection or a bad intermittent switch????