Heated Rear Window

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.

Heated rear window operation is only enabled when the engine is running. The ATCM controls operation of the heated rear window

using a relay in the RJB (Rear junction Box). When a request is made for heated rear window operation, the ATCM broadcasts a message to the BCM/GWM on the MS CAN comfort systems bus, the BCM/GWM. On receipt of this message, the RJB energizes the relay by providing a ground path for the relay coil. This allows a battery feed to flow across the relay to power the heater element.

There are 2 modes of heated rear window operation; manual and automatic.

Manual operation is activated by pressing the heated rear window switch. When the switch is pressed, the status Light Emitting Diode (LED) in the switch illuminates and the rear window heater element is energized. Manual operation is discontinued when the heated rear window switch is pressed a second time, between 5 and 21 minutes have elapsed (dependent on ambient air temperature), or the engine stops. If manual operation is discontinued by the engine stopping, the previous heating phase is resumed if the engine is re-started within 30 seconds.

There are 2 variants of automatic operation; automatic operation at the start of a journey and automatic operation during a journey.

Automatic operation at the start of a journey is initiated for between 5 and 21 minutes (dependent on ambient air temperature). The higher the ambient air temperature, the shorter the time. In this instance, the switch LED is illuminated and the heater element is energized. In addition to shorter operating times in temperate winter conditions, there are condition qualifiers to prevent subsequent operations once the cabin or engine is warm, or there is a significant sunload. Automatic operation is discontinued if the heated rear window switch is pressed or the engine stops

NOTE: This feature can be selected on and off on the Settings page of the Climate menu in the touch screen.

Automatic operation during a journey is initiated when low ambient air temperatures are experienced and the vehicle has been traveling for a set period of time above a threshold speed. In this instance, no feedback is given to inform the driver that the heated rear window is operational (the switch LED is not illuminated) and the duration of operation is variable depending upon the ambient air temperature, vehicle speed and the amount of time the vehicle has been travelling.