Electric Booster Heater

WARNING: This page is about a different car, the 2020 Jaguar XE and 2019 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

The electric booster heater consists of a matrix, containing ceramic coated positive temperature coefficient elements, which is installed in the climate control assembly.

Operation of the electric booster heater is activated by the Rear Junction Box (RJB) and the two electric booster heater relays, integral with the RJB. The RJB activates the electric booster heater relays to energize combinations of the three electric booster heater elements as required.

The HVAC Control Module uses the following inputs from the High Speed (HS) Controller Area Network (CAN) comfort systems bus, to control operation of the electric booster heater:

Climate control system selections from the Integrated Control Panel (ICP) and the Touch Screen (TS), through the HS CAN comfort systems bus.
Ambient air temperature and engine coolant temperature from the Powertrain Control Module (PCM) via the HS CAN powertrain systems bus via the Body Control Module/Gateway Module (BCM/GWM) assembly.
Battery state from the BCM/GWM assembly through the HS CAN comfort systems bus.

The HVAC requests operation of the electric booster heater, provided the vehicle is not in transit mode and there are no generator faults recorded, when the following conditions occur:

The engine is running.
The blower is on (any speed).
Heating is requested on the ICP, or on the menu of the TS, and the desired vent temperature (calculated by the HVAC), is not being achieved.

The electrical booster heater elements activated by the HVAC which is proportional to the amount of heating required. If the electrical load management is in force, the electric booster heater performance is reduced.