I emailed Lewmar, have corresponded a bit with Josh McAnany there (firstname.lastname@example.org). He said the extra unused black wire they call the "fifth wire" and is supposed to be unused unless you're using the thruster in conjunction with an automatic battery
I tried swapping the dual thruster controller on the flybridge with the one in the lower helm, and strangely they both seemed to work for some period of time. Then the one in the lower helm (which had been malfunctioning previously in the flybridge) started malfunctioning in a much more disturbing way: when I turned the controller on with the power button, the bow thruster would drive to one side, and stay on until I touched a joystick, at which point the whole controller would turn off completely. I told Josh about this problem and he asked what happens when I swap them back -- haven't had time to try it yet. I mainly use the thrusters from the flybridge, so once I got the working one up there, wasn't as motivated to mess with it, but as a result I don't have any controller installed in the lower helm at the moment.
When I bought the boat a couple years ago, we had a mechanic
servicing some issues found in the inspection
, and he said while he was down working on the engine
, one of the thrusters just suddenly turned itself on full blast until he got to the battery
switch and turned it off. We had an electrician look at it, and could never reproduce the failure, so I just turn off the battery switches whenever I'm at the dock
just to be sure they don't come on by themselves. Would obviously be dangerous for that to happen anytime that you're not tied up and bumpered to a dock
What I think is happening is that the electronics
inside of the controller are starting to gradually degrade, showing these intermittent symptoms. However, the controller electronics
are potted in epoxy
so I can't get in there and debug further or replace a failing transistor or IC.
Can you describe what you're seeing a bit more? Do you know how old your controller is? Mine has a code "0511" in the upper right of the sticker which if it's a date code would mean May 2011, which would make sense as that was around when the previous owner was doing a lot of upgrades. Attaching a photo
of the sticker.