The rear window defroster only works when the ignition key is turned to position 1 or 2. When the rear window defroster is turned on, the control LED on the switch button lights up.
The rear window defroster draws a very large amount of current, so turn it on only for the time needed to clear the rear window from misting. The rear window defroster will automatically turn off after 15 minutes of operation.
When several powerful consumers of electricity are switched on and the battery capacity is low, the rear window heater is automatically switched off and in this case the control LED flashes. When the voltage in the vehicle's on-board network increases, the rear window heater automatically turns on.