Description And Operation: Overview

WARNING: This page is about a different car, the 2018 Jaguar XE and 2017 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

Due to the slower warm up times associated with the engine, an electric booster heater may be fitted to increase heater performance. The electric booster heater does this by heating the air leaving the heater assembly. The electric booster heater comprises ceramic coated thermistor elements. A request for electric booster heater operation originates in the Automatic Temperature Control Module (ATCM). This request is in the form of a relay energize signal to the Rear Junction Box (RJB) and the electric booster heater relays, integral with the RJB. This then provides power to the three sections of the electric booster heater, in accordance to the demand for heating.

The amount of heating requested by the ATCM is based on:

Ambient air temperature.
Engine coolant temperature.
Heating request.

NOTE: There is also a minimum blower-motor speed required for the electric booster heater operation.

The electric booster heater is limited to 1 kW. If electrical load management is in force, electric booster heater performance will be reduced.

Depending on model specification and market, the vehicle may incorporate auxiliary heating in the form of a Fuel Fired Booster Heater (FFBH). The FFBH boosts the temperature of the engine coolant supplied to the climate control assembly.

Fuel for the FFBH is taken from the vehicle fuel tank, through a fuel line attached to the fuel pump module. A FFBH fuel pump supplies the fuel at low pressure to the FFBH. In the FFBH, the fuel is burned and the resultant heat output is used to heat the engine coolant, which is circulated through the climate control assembly by a FFBH coolant pump.

FFBH operation is automatic while the engine is running. Where timed climate control is incorporated, the FFBH can be selected to operate (depending on the ambient air temperature) while the vehicle is parked using the Touch Screen (TS) or a remote control.

Vehicles with timed climate control also incorporate:

A FFBH receiver for communication with the remote control.
A changeover valve that allows the climate control coolant circuit to be isolated from the engine coolant circuit to reduce the warm up time of the passenger compartment.