That rubber dome that appears to be some sort of a light is actually a weatherproof cap covering the circuit-breaker reset for the battery pack. In the event of an overload situation, the circuit breaker would trip and you would see a little button appearing inside the dome. To reset the circuit breaker, you would just push on the dome/button. This circuit breaker protects the motor and drive train from damage.
The circuit breaker can trip when:
1. The total weight capacity of the scooter is exceeded.
2. Attempting to climb too steep of an incline.
3. Operating for extended periods of time in unusually high temperatures (greater than about 100 degrees).
Note that the scooter may requre a cool-down period of two hours before resuming operation. Tripping of the circuit breaker rarely indicates a defect with the scooter.