Heater Core Temperature Sensor / Switch: Description and Operation

TEMPERATURE CONTROL LOCKOUT VALVE AND SWITCH
^ Its function is to prevent operation of the blower motor when the engine coolant temperature is below 45°C (113°F).
^ When the coolant temperature exceeds 45°C (113°F), the temperature control lockout valve and switch opens, turning the blower motor on.
^ The temperature control lockout valve and switch will not prevent A/C blower motor operation when defrost is required.
^ The temperature control lockout valve and switch is located in the heater core inlet hose tube in the engine compartment.