Fuel Fired Booster Heater Coolant Changeover Valve (Vehicles With Timed Climate Control Only)

Where fitted, the Fuel Fired Booster Heater (FFBH) coolant changeover valve is attached to a bracket on the underside of the FFBH. The FFBH coolant changeover valve is a normally open solenoid valve installed between the supply and return sides of the heater coolant circuit. When de-energized, the FFBH coolant changeover valve connects the heater coolant circuit to the engine coolant circuit. When energized, the FFBH coolant changeover valve isolates the heater coolant circuit from the engine coolant circuit.

Operation of the FFBH coolant changeover valve is controlled by a power feed from the ATCM (Automatic Temperature Control Module).