Yanmar 3jh3ce wiring question.

[Captain Bill]

I am currently tracking down a problem with my Tachometer on my 3JH3CE. My wiring harness got dowsed in saltwater last year after a heat exchanger failure. I suspect that the wiring harness has been compromised despite a liberal cleansing with RO water and a good soaking in WD40. Continuity checking seams to indicate that the problem lies in an obscure piece of the harness associated with the sail drive water sensor. The sail drive parts manual calls it an amplifier and some other reseach indicates that this amplifier amplifies the signal from the sail drive water sensor and acts as a breakout box for the saildrive wiring. The "amplifier" has two connectors that insert into the Engine wiring harness and the Harness extension that runs up t the instrument panel. Does anyone know if it's safe to simply remove the "amplifier" and plug the harness extension directly into the Engine harness, at least for diagnostic purposes? I know I would loose the water sensor input, but I'm more concerned with blowing up something else. The harness is in a difficult place to reach and none of my many pairs of reading glasses seem to work at the distance between the place I must put my head and the harness in order to see if there are any wiring color differences between the connectors on the engine Harness and extension. I suspect there will be no connetions on the engine side where the water sensor is integrated. The wiring diagrams in the owners manual, service manual, and parts manual are of no help because this part is not shown in any of those manuals. I found it in the parts manual for the sail drive, but it shows no wiring information. I love well documented products, unfortunately this is not one of them.