Seal Alarm

[Dan Corcoran]

Troubleshooting the seal drive alarm, found that that the supply voltage measured at the sensor is about 5v.

The output voltage on the white/yellow wire input into the alarm reads
0.64 vdc when the sensor is not submerged
0.71 vdc when the sensor is submerged

Unsurprisingly no light or buzz.

It appears that there may be a relay or some electronics hiding somewhere, maybe this is it:
https://j109.org/docs/yanmar-sd20-saild ... atalog.pdf
Figure 5

Same here:
https://www.maritimepropulsion.com/files/pdf/1001374
Diagram 9

I see the part 196420-02811 Yanmar Amplifier is $457 USD (not a typo) from various suppliers including Toads Marine, Discount Marine,

Any hints before I invest some more time into this?