Update on the mystery blower
Appreciate the great information. Thank you.
On the boat today, I did 2 tests.
1) The blower did not run when the ignition switch was on. Beep-beep-beep and no blower.
2) I hot-wired the blower directly to the 12v batteries. It ran but was pretty loud. It sounded a bit like gravel, as if the bearings were shot.
Maybe the PO disconnected it somewhere because it was running loud. But if so, why not disconnect it at the unit, with the easy disconnect plugs right there next to it.
Next steps: 1) Check to make sure there's no switch at the helm that I am missing. 2) With my multimeter, verify no 12v is getting to the blower. 3) Then try again to trace the wires after they start going behind things.
And 4) Guess I need a new blower. 3 bolts and it's off the wall, then removing the flexible tube from it. After I get it out, I can see what make it is. (And since this doesn't have to be done pre-launch, this is not super high priority right now. I have a spalding keel to fix, a rear rubrail area to fix, and seacocks to replace, among other things.)
Fun fact #2484: In my avatar, that's DavidPM at the helm of my boat.
Bland, non-political statement goes here.