Rear Demist

Fig 1: Identifying Rear Demist

Courtesy of VOLVO CARS CORPORATION

There are heating loops in the glass for demisting and to prevent ice from forming. The loops heat up when they are supplied with power. The power supply is via a relay in the central electronic module (CEM).

Rear demist is controlled using a switch on the right-hand side of the climate control module (CCM).

Press the button again to switch off the function. Demisting is switched off automatically after the maximum time of 12 minutes.

By starting the rear demist, together with other actions, the vehicle's alternator is loaded and the engine coolant temperature rises.

There are diagnostics for the relay and switch.