Transducer troubleshooting

[LeoKa]

My Garmin chart plotter is showing error messages about the transducer not being connected. The boat was hauled out in December and the bottom was cleaned. There is some growth on the hull, but not significant.
The Garmin functions fine and it has the latest software installed.
How do I troubleshoot this connection problem?
I will attach some photos.
Thanks.

 

[LeoKa]

 

[JDCAVE]

It’s not clear from the 2nd photo where the transducer cable connects to the unit.

 

[LeoKa]

It’s not clear from the 2nd photo where the transducer cable connects to the unit.

The blue connector. 8 pin sonar.

 

[JDCAVE]

How is the voltage going into the unit? Sometimes this is a low voltage issue. That’s low hanging fruit that’s easy to check with a multi meter. If that checks out ok, then there is probably a multimeter test on the transducer cable connector that can test for continuity issues. Others on the forum could advise.

 

[JDCAVE]

There was some discussion on this topic here:
http://www.trawlerforum.com/forums/s4/testing-depth-transducer-24870.html

 

[LeoKa]

There was some discussion on this topic here:
http://www.trawlerforum.com/forums/s4/testing-depth-transducer-24870.html

I have read it. Good info.
The end of the story is interesting though. I am close to a navy yard, but I will do the wire tests first.