There is a power supply line tied together at the dash in a Star Connector (4 way splitter) and that power supplies the bow on older boats. Odds are it is in either the 12 gauge positive power wire or ground feeding to the bow from the dash.
Through the panel, or under the console, you can find the wires and see what the issue is. If someone has added units or something to power we would check that connection first.
BCB
Further:
Around 2015 model year we began using a graph (depth finder) dedicated 6 gauge soldered power line to the dash with a terminal block and a 10 gauge soldered connector to the bow. While we do offer it, We are not trying to sell the feature here. It was built because of common Lowrance, bench and technical trouble shooters, constantly accusing boat builders of having too small a wire feeding power to graphs. After this we began use of a standard deep cycle high CCA, 31 series AGM battery also.
That occasional low power shut down has somehow not been solved after the addition the new excessive clean power harness. And the depth finder companies have not addressed the excessively small wire and inexpensive connections that are powering the units either.
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