My Lowrance HDS 7 on the bow of my boat will turn on, then flash off/on. I have checked the connections and all is good. Anyone else dealt with this?

Are you wired to the boats wiring harness or directly to battery. Would highly recommend bypassing the boats fuse panel or harness and going straight to battery with online fuse at battery

Has the unit been working fine and just started what you have described or did you just install the unit and this is how it is operating from day one?

Usually when flashing on and off, if it is a new unit, it comes back to a low voltage issue, which could me undersized wiring or not connected correctly. If it's and older unit, on Lowrance it could be water intrusion or a bad key pad.
John

It was working fine until the last trip out it started doing that. I checked all the connections which were tight, but I cleaned everything then reconnected. I am headed to Rayburn tomorrow, hopefully it was just a poor connection that I didn't see...

I have seen many power cables fail over the years. Make sure that the pin connections inside the graph are clean as well as the cable. Also check the fuses and their sockets I use sand paper and dielectric grease to clean then protect the fuses. Some electronic stores have pin style files. I have repaired a few by cleaning said areas but their always lies the possibility that there is a break in the power wiring which is very difficult to repair.

I had a 12 on console and 7 on bow connected to a single on/off power switch. My bow unit began doing same as yours. Ran dedicated power from battery to 7 on bow. Problem solved.

I might try this, mine is currently ran how yours were.

weak battery..?

It def sounds like it is a voltage issue...running direct on the larger units is good practice vs trying to load all of the units onto one power switch. Especially if running 2+ units that have a large screen size.