Accessory
socket
Temp
sensor
Sonar unit with external temp sensor, external speed sensor, or combo
speed/temp sensor. The primary temperature sensor is built
Optional Speed Sensor Installation
All the units in this series can display speed and distance traveled, but
only the SeaFinder 640c DF comes packed with a speed sensor. If you
wish to purchase an optional additional sensor for your unit, refer to
the accessory ordering information inside the back cover of this man-
ual. The following instructions describe how to install the speed sensor.
Speed sensor or
combo speed/
temp sensor.
into the transducer.
Sonar unit rear view
Power/transducer socket
Power/transducer
cable
Temp sensor built
into transducer.
27
3-amp fuse