RAM 2500 Van V8-5.9L VIN Z (1997)
Heater Control Valve: Description and Operation
WATER VALVE
A vacuum-actuated water valve is used to control engine coolant flow to the front heater core. A second vacuum-actuated water valve is used to
control engine coolant flow to the rear heater core, on all models with an optional rear heater.
When vacuum is applied, the water valve closes and coolant flow is bypassed back to the engine. When the valve is opened (no vacuum applied),
the coolant flows through the heater core and back to the engine.
Vacuum to the front heater core water valve is controlled by the push button mode control switch. Vacuum to the rear heater core water valve is
controlled by an auxiliary vacuum switch that is actuated by the temperature control lever.
The water valve cannot be repaired and, if faulty or damaged, it must be replaced.
