Age and Resistance
If this is about the rectangular black plastic multi-wire connector from the engine area to the cockpit panel... AFAIK that's there to facilitate assembly of the new boat.
We have one that is in the engine compartment and routes
all the engine-related wiring from there back to the panel in the cockpit.
When they built the boats this allowed separate areas of the boat to be assembled and finally the plug was put together and taped up with black plastic tape.
Like Ralph, I have run into a case of internal resistance in this plug. Back when trouble shooting our electric fuel lift pump I found a voltage drop in the supply wire to the pump (and other parts on that circuit) and bypassed that one wire with a new wire direct to the cockpit panel.
I have sometimes pondered if it might be a good idea to simply install a piece of flex conduit and pull new wiring, in all of their glorious different colors, between both ends...
OTOH, perhaps by the time the next wiring failure occurs (?) we will have enough time on the old engine to justify a new engine package! And then the
next owner can worry about these problems in
another 25 years.
Best of Luck Ralph!
I sure enjoyed sailing with you on your visit to Portland!
Loren