Just wondering whether the screen wash warning light comes on when the bottle is completely empty, or if it leaves a reserve?

27 minutes ago, Mr Statto said:

Just wondering whether the screen wash warning light comes on when the bottle is completely empty, or if it leaves a reserve?

There is some screen wash left but at times during this winter I put 2 litres in both our cars without the warning light even coming on. This tends to be one my weekly checks when I clean both cars.

There is indeed a “reserve” left.  I believe headlight washers are deactivated during this time as well. 

A good idea to know with the vehicle you are asking about is before winter comes again let the warning activate and find out for yourself, 

then you know how long or how much washer is available and how much needed as you top it up.