Garmin GPSMAP 12 2 Series Installation Instructions Manual page 12

Lamp and Horn Connections
The device can be used with a lamp, a horn, or both, to sound or flash an alert when the chartplotter displays
a message. This is optional, and the alarm wire is not necessary for the device to function normally. When
connecting the device to a lamp or horn, observe these considerations.
• The alarm circuit switches to a low-voltage state when the alarm sounds.
• The maximum current is 1 A, and a relay is needed to limit the current from the chartplotter to 1 A.
• To manually toggle visual and audible alerts, you can install single-pole, single-throw switches.
Item Description
Power source
Power cable
Horn
Lamp
Relay (1 A coil current)
Toggle switches to enable and disable lamp or horn alerts
Item Wire Color
Red
Black
Yellow
12
Wire Function
Power
Ground
Alarm