Heater Unit: Description
An electric positive temperature coefficient (PTC) heater unit (1) is used on vehicles when equipped with the 3.0L diesel engine. The PTC heater unit aids in passenger compartment heating by compensating for the slower warm up rate of the diesel engine.
The PTC heater unit is located in the HVAC air distribution housing, downstream of the heater core and is controlled by the diesel engine control module (ECM) through three relays.
The PTC heater consists of three heating elements with fins (2) that transfer the heat to the conditioned air flowing within the air distribution housing and a retaining feature (3) that is molded onto end of the PTC heater unit to support the heater unit inside the air distribution housing. The PTC heater unit is connected to the vehicle electrical system by a ground strap (4) and a plastic wire connector with three terminals (5) which is connected to the headlamp and dash wire harness. If service of the PTC heater unit is required, a plastic mounting plate (6) is provided with the replacement heater unit.
The PTC heater unit can be accessed for service from underneath the instrument panel.