Press "Enter" to skip to content

Parts2K Parts Diagram Lookup Posts

Thermostat Wiring Diagram With Terminal Labels and Color Codes for HVAC Systems

thermostat wiring diagram

Check the terminal letters on the wall climate controller and match each conductor by function before attaching anything. Most residential heating and cooling setups run on a 24-volt control circuit, where each lead connects a specific component such as the furnace relay, cooling contactor, or fan control. Correct placement prevents short circuits and avoids damage to control boards.