Heater Control Valve: Description and Operation
Dual Coolant Control Valve:
The dual coolant valve regulates the flow of engine coolant to each half of the heater core. Two electric solenoids, Which are individually actuated by the heater control module, are the control elements. The valve contains five ports:
inlet port - coolant from the engine
outlet port - coolant to driver side of heater core
outlet port - coolant to passenger side of heater core
return port - common coolant return from heater core
outlet port - coolant return to engine