Turning the key to MAR the warning light on the dial turns on, but it should go off as soon as the engine is started.
If the 
warning light turns on when
the car is travelling (on certain versions together with the message on the display),
stop the engine immediately and contact a Fiat Dealership.
See also:
Main beam headlights
To change the bulb, remove the protective cover (1), release the catch (A) and
remove the bulb (B). ...
SOUND system
Large oddment compartments in the dashboard and doors which make the passenger
compartment even more comfortable can be fond in cars not equipped with a sound
system set-up.
A specific kit can be ...
Rear window and door mirror demisting/defrosting
Press to turn this function on.
Activation is indicated by the turning on of the warning light
on the instrument panel.
This function is timed and switches off automatically after 30 minutes. To ...