Testing The Installation - Garmin GPSMAP 178 Owner's Manual

Appendix A

Testing the Installation

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Testing the Installation
While it is possible to perform some checks with the boat trailered, the boat should be in the water
to properly test the sonar portion of the installation.
Press the POWER button and the GPSMAP 178/178C should power on. If the unit fails to power
on, verify that the wiring adapter is seated properly in the back of the unit, the Red and Black wires are
connected to the correct polarity, and that the fuse is installed and not blown. If the unit is connected to a
power supply that exceeds 35 VDC, a "Battery Voltage High" warning is displayed and the unit turns off.
Since water is necessary to carry the sounder' s sonar signal, the transducer must be in the water to
work properly. It is not possible to get a depth/distance reading when out of the water. As the unit powers
on, it should immediately start showing the bottom. Verify that the unit is not in the simulator mode. If
the unit is in the simulator mode, make sure that the transducer is connected to the wiring harness.
To test the transducer installation, gradually increase the boat speed while checking the unit opera-
tion. If the unit displays intermittently or fails to display, verify that the transducer is aligned parallel
with the bottom and if necessary, adjust the transducer height until the unit operates correctly. It may be
necessary to make several adjustments to ensure proper operation throughout the speed range.
F
NOTE: When adjustng the depth of the transducer, make the adjustments n small ncre-
ments. Placng the transducer too deep can adversely affect the boat's performance and
put the transducer at greater rsk of strkng underwater objects.