830 3 cyl diesel alt ?

70?s model 830 diesel 3cyl batteries not staying charged. Alt had a plug in with 3 wires. There are 2 legs one has a red wire and a black wire that comes from a module attached to it. The other leg has nothing on it. There is a black wire in the harness that has a plug on it not attached to any thing. Anyone have an idea where it would go. Haven?t been to dealer to check about a wiring diagram.

How long have you had the tractor? Are the batteries discharging while it sets or not charging after you get it started? Did you replace the alternator and in doing so the wiring changed? Or is your problem just the batteries are not holding a charge? That is not clear. If it was working ok and you haven't done anything that changed the wiring, that shouldn't be the problem.

If you have the manuals the wiring schematic should be in it. In the parts catalog it looks like those tractors used at least three different alternators. The regulators mounted on the back of them it appears. The wire may or may not be needed, depending on the system and accessories.

Start with the basics. Have you disconnected the batteries, cleaned all the terminals at both ends of the cables? Then separately charged and tested the batteries? A bad battery can discharge others connected to it.

Fan belt tight? Have you checked the output of the alternator? You can do a parasitic drain test to see if there is something pulling the battery down while it is setting.

No offense intended by any question, just don't know the background info, which can help get you a better answer.

Nothing has been touched on the tractor since I have had it.
Batteries have discharged a couple of times due to me leaving
a switch on. When I jump start it and run it for 3 or four hours
it will not charge on it?s own. I will check belt. Batteries may
need replacing. I haven?t had them checked. It has two and I
hope the former owner had them installed correctly. I saw the
wire that was loose and was just wondering if it was supposed
to be hooked to the alternator. Will try to find a wiring diagram.

Dave, Think I may have a book with a wiring picture. Will look and get back to you.

That would be great. thanks