Heater, Transmission: Operation: Operation
WARNING: This page is about a different car, the 2013 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
Coolant not required for cabin heat is directed to the transmission heater. Coolant flow is directed by a pulse width modulated ball valve located upstream of the cabin heater coolant supply. Coolant first goes to the 3-way valve inlet port. The coolant valve receives a signal from the engine controller directing to turn the ball valve in accordance with the heater demand. The transmission heater is an assembly containing an oil-to-water heat exchanger and a Thermal Bypass Valve (TBV). The coolant that is sent from the 3-way valve warms the transmission fluid in order to get it up to the ideal operating temperature.