Brake light coming on

Just had the 110 serviced about 1k ago, now the brake light is coming on when I go downhill and brake fairly firmly

Is this likly to be a loss of fluid (not checked the level yet) also is the correct level obviously marked on the side, no idea how much it needs? I assume all brake fuild is the same right?

Any advice gratefully recieved

Cheers
Togg

30 secs of research and I see brake fluid is not all the same...who knew?

brake fluid low or more likely it's that the brake pads are low or the wear indicator wires are trapped if he brake pads have recently been done. (assuming it has wear indicators)