Question id 301 - Aircraft General Knowledge - Airframe, Systems, Powerplant - ATPL - Airline Transport Pilot license

Only the position of the selector switch.
A green system "ON" information light and an amber system failure light.
Amber lights when the system is functioning with a red warning should the windscreen enter an overheat condition.
Green or blue lights which cycle on/off with the function of the heating elements.

Training tests and timed exam simulations ATPL - Airline Transport Pilot license