The needle shows the fuel present in the tank. When the fuel reserve warning light A-fig. 35 - 36 comes on (on certain versions with the dedicated message on the reconfigurable multifunction display) it means that there are approximately 5-7 liters of fuel left in the tank.
E - tank empty.
F - tank full.
Never travel with the tank almost empty: lack of fuel could damage the catalyser.

IMPORTANT
The needle will point to E and the reserve warning light A will flash to indicate a fault in the system. Contact a Fiat Dealership to have the system checked.
See also:
Tread Wear Indicators
Tread wear indicators are in the original equipment tires to help you in determining
when your tires should be replaced.
1 — Worn Tire
2 — New Tire
These indicators are molded into the bottom o ...
Fiat 500 Owners Manual
h1 {color: red;}
h2 {color: green;}
h3 {color: blue;}
h4 {color: #FF00FF;}
...
Manual climate control system (where provided)
The climate control system is adjusted manually.
CONTROLS fig. 78
A - Knob for operating the fan and switching the climate control system on and
off.
The climate control system can only be switch ...


