B Series Truck 2WD L4-2184cc 2.2L 2200 2-bbl (1990)
EFE Relay: Description and Operation
PTC Heater System
The throttle body heating system heats up the throttle body of the carburetor to prevent the carburetor from icing. The system consists of the PTC
heater, PTC heater relay, and coolant temperature switch. The heater operates when the radiator coolant temperature is less then 17°C (63°F).
PTC HEATER
The PTC heater is located between the carburetor and the intake manifold. The heater is controlled by the PTC heater relay.
PTC HEATER RELAY
The PTC heater relay supplies power to the PTC heater. The relay is controlled by the coolant temperature switch.
