Honda Rebel 2017 Owner's Manual page 30

Indicators
(Continued)
28
High beam indicator
Turn signal indicator
ABS (Anti-lock Brake System) indicator
CMX300A only
Comes on when the ignition switch is turned to
the ON position. Goes off when your speed
reaches approximately 6 mph (10 km/h).
If it comes on while riding:
Neutral indicator
Comes on when the transmission is in Neutral.
(P.95)