depth finder no power

took our boat out recently and the depth finder, blower, horn, lights all failed to work. I have tried to turn these one from the switch panel - no luck. The fuses appear to be ok (all lit up when pushed fuse test button on EIM). I do not see any loose wiring. any suggestions on how to...

Looking for some help with where to start - I have an older depthfinder but it works as it should when it comes on. When I turn it on at the dash sometimes it comes on, sometimes it doesn't. With that being said, it isn't the fuse - do I check and clean the connections? Should I take the dash...