Honda GL1800D Owner's Manual page 49

Combined ABS indicator
Comes on when the ignition switch is
turned ON. Goes off when your speed
reaches approximately 3 mph (5 km/h).
If the indicator comes on while riding:
(P175)
High coolant temperature indicator
Comes on briefly when the ignition switch
is turned ON.
If the indicator comes on while riding:
(P174)
Parking brake indicator
GL1800BD/D/DA
Comes on as a reminder that you have not
released the parking brake lever. (P60)
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