DV24 alternator wiring

[tonyp]

There is a wire from the wiring loom that has never been connected to the alternator on our boat. A new alternator had been fitted the year before we bought the boat, but the wire obviously not connected to anything.   As far as I can tell everything is working as normal, but I'd very much like to work out where it should go, if anywhere.  I think the alternator is a Bosch, but that's a guess.



The wire is black, which suggests it may be a ground. (The others are red, violet and orange.) The ground on the alternator is labelled as B-, and can be seen in the pic as the right upper terminal.  (The positive from the alternator is labelled B+, no idea yet what the other two are labelled. I expect a D and a W). Testing the wire with a meter could prove it is a ground, (I haven't checked it yet) but if the test proves negative it won't prove that it's not. So before I go tracking wires through the boat's bowels and back to the instrument panel, does anyone know the colour coding for the 4 wires that come from the loom to the alternator or, if you have a four-wire connected alternator, where is your black wire connected?

Tony

[oceandancer]

Hi Tony,
Have you by any chance got, or have in the past had, a smart regulator fitted? The sort of device made by Sterling Power. They require an additional cable to be connected to the alternator in conjuction with a small modification to gain direct access to the rotor. This cable does look as if it goes into the regulator.. Can you see any signs of a small box having been fitted in the battery compartment ? Or redundant wiring that has been cut back?

Regards

Mick

[tonyp]

Thanks, Mick, There are quite a few bits of "freestyle" wiring and a few loose ends on the boat, ( not surprising after nearly 40 years), so I'll have a look first. I must say, I haven't seen anything like you describe, but you never know.

Tony