It could be the beaker itself. The ETA Breakers do age with moisture. They are higher quality and were Great for their time, though that was almost 30 years ago. The other factor is to chase the terminal block at the transom, though in this case thats highly unlikely. Corrosion is not nearly the issue on pre 1992 model as extended parasitic drains that allow corrosion, from trickling voltage, did not happen till items remained ina sleep mode. Things like engines, electronics, stereos, and more all have a parasitic drain today. That was not common in the pre-1990s boats. BCB