Doing a favor for a friend, his tenant removed thermostat and disconnected all wires at AC and Heater. I need to know how the relay is triggerd form T stat?. and what are the 3 wires in the ac unit wired to at stat. I have a control wire from FAU and CA both going to stat. I believe this is a split system with the compressor out side and a coil in FAU ?
Any help or diagrams..