Lowrance LMF-400 Installation And Operation Instructions Manual page 10

Secure unit to the dash using "U" bracket as shown.
The bracket is designed to secure the unit to a dash with a thickness of
2 mm. If your dash is thicker than 2 mm, the "U" bracket will be too
long. Simply place washers or spacers between the unit and the bracket
until you can tighten the wing nuts and secure the unit in place. You
are now ready to wire the unit to the buzzer (piezo) and dash lights.
LMF-400
Housing
LMF-400 with power cable wiring and NMEA 2000 Cable Connection.
Connecting the LMF-400 to the buzzer (piezo), will enable the buzzer to
sound when buttons are pressed and when alarms and level warnings
are triggered. Wiring the unit to the boat's dash lights, will turn on the
LMF-400 backlight when the dash lights are turned on.
Yellow wire:
Piezo ground
Blue wire:
Piezo positive
4
White wire:
Dash light
positive
Black wire:
Dash light
ground
LMF-400
NMEA
2000
Network
Cable