Garmin 521 Installation Instruction

The chartplotter comes with a wiring harness that connects the chartplotter to power and to optional NMEA 0183 and Garmin CANet devices. 

If applicable, the wiring harness also connects the chartplotter to a transducer.
The wiring harness does not connect to a NMEA 2000 network. For instructions on connecting to a NMEA 2000 network with compatible 

devices, see 

.

Use an AGC/ 3AG - 3 Amp replacement fuse.
If it is necessary to extend the power and ground wires, use 22 AWG wire.
You can wire the harness directly to the battery, or if your boat has an electrical system, you might be able to wire the harness to an

unused holder on the fuse block. If you use the boat fuse block, remove the in-line fuse holder on the power wire of the harness.
Do not cut the transducer cable, because this voids your warranty.

  NotIce: The maximum input voltage is 32 Vdc*. Do not exceed this voltage because this can damage the chartplotter and void the warranty.

NOTE: During a typical installation, use only the red and black wires. The other wires do not have to be connected for normal operation of the 

chartplotter. For information on connecting to a NMEA 0183- or Garmin CANet-compatible device, see 

1.  Use a test light or voltmeter to determine the polarity of the voltage source.
2.  Connect the red (+ or positive) wire to the positive voltage terminal. (If you use the

fuse block on the boat, route the positive connection through the fuse, as shown on the

diagram.)

3.  Connect the black (- or ground) wire to the negative voltage terminal.
4.  Install or check the 3 A fuse (in the in-line fuse holder, or on the fuse block of the boat).

•
•
•

•

2A

3A

-

+

2A

3A

-

+