See also:

Treadwear indicators
Narrow bars (tread wear bars) that are distributed over the tire tread. If the tire tread is level with the bars, the wear limit of 1/16 in (1.6 mm) has been reached. ...

Switching on/off
The three red indicator lamps in the button indicate the heating level you have selected. If the battery voltage is too low, the seat heating may switch off. One or more of the indicator lamp ...

Brake fluid
WARNING Over a period of time, the brake fluid absorbs moisture from the air; this lowers its boiling point. If the boiling point of the brake fluid is too low, vapor pockets may form in t ...