YYK is a model prefix for a series of electronically commutated motors (ECM) or permanent split capacitor (PSC) motor controllers used by brands like Gree, Midea, and other Asian HVAC manufacturers. Always verify your specific unit's voltage (typically 230V or 115V AC) before wiring. Understanding the YYK Controller Wiring Diagram The YYK controller is a compact PCB that converts control signals (from a thermostat or main board) into motor speed commands. Below is the standard terminal identification and wiring logic. Terminal Layout & Functions Most YYK controllers have 5-7 terminals. Refer to the diagram below: