Maximum Demist

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

When the MAX demist switch on the Integrated Control Panel (ICP) is pressed, the Automatic Temperature Control Module (ATCM) configures the climate control system as follows:

Automatic mode off
A/C on
Selected temperature unchanged
Air inlet set to fresh air
Air distribution set to windshield
Blower speed set to high speed.

The ATCM also sends a High Speed (HS) Controller Area Network (CAN) Power Mode Zero message through the Body Control Module/Gateway Module (BCM/GWM) to activate the windshield and rear window heaters.

The programmed demist function can be cancelled by one of the following:

A second press of the MAX demist switch
Selecting any air distribution soft key on the touch screen
Pressing the driver side AUTO switch on the ICP
selecting Power Mode 4 or lower.

The blower speed can be adjusted without terminating the programmed demist function. If the blower speed has been adjusted and then the MAX demist switch is pressed again, the system will go back to the MAX demist default settings. If the MAX demist program is cancelled with the MAX demist switch or the driver side AUTO switch, the windshield and rear window heaters remain on until they time out.