See also:

Operating the System
If you do not operate the    system from the front panel for more than 20 seconds, the indicator in the button goes off, and the front display returns to what has previously been displayed ...

Wear Indicators
The groove where the wear indicator is located is 1/16 inch (1.6 mm) shallower than elsewhere on the tire. If the tread has worn so that the indicator is exposed, replace the tire. Worn out tires ...

Lights
Light Control Switches ...