Heater Control Valve: Description and Operation

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Part 2:

The dual coolant control valve regulates the flow of engine coolant to each half of the heater core. Two electric solenoids, which are individually actuated by the Dual Automatic Temperature Control (DATC) module, are the control elements. Based on inputs from the DATC module the solenoids cycle open and closed to regulate the coolant flow to the heater core. The solenoids can be cycled at different speeds by the DATC module in order to maintain different temperatures for each half of the heater core. Under certain conditions when heating is not required, the dual coolant flow valve will bypass the heater core by closing both solenoids and routing the coolant back to the engine cooling system. The valve contains five ports.