In the event of high outside temperatures, the windscreen heater may not switch on.
If the indicator lamp on the button lights up, the windscreen heater has switched on.
The windscreen heater switches off automatically after a few minutes.
If the battery voltage is too low, it may not be possible to switch the windscreen heater on. If the battery voltage becomes too low while the windscreen heater is in operation, the windscreen heater will switch off automatically.