Farmall MD Wiring Help

Ok so I am converting my 1951 Farmall MD to 12V with an internally regulated alternator. I bought a low-cut in 1-wire alternator and wiring harness from the Brillman Company. I was told it would be the correct wiring harness to allow me to delete my voltage regulator and switch from the generator. I am having problems getting everything hooked up. My old wiring is mostly gone so no help at all. According to the direction from the Brillman company here is what I have:

Negative ground off battery. Positive to starter button, starter button to starter. Starter button to - ammeter. + ammeter to BAT on alternator. + ammeter to fuse, fuse to #3 on light switch.

Now there is a wire that also goes to #3 on the light switch but not sure where the other end goes??? Also have a wire running from that same area to the front of the tractor but not sure what it is for. Tractor will start (magneto) and run but the ammeter gage never moves (it works - i previously tested it) and the alternator does not charge. What do I need to do differently??? Any help would be appreciated!!! I have looked at farmallbob wiring diagrams and cant seem to figure anything out...

The other terminals on the light switch might have been for the 4th terminal on the VR (L terminal). It should probably be connected to the Amp meter load side. (if the light switch has 4 positions it might be a regulator control type light switch, but it would not have been original that way.
The alternator should put out 14.2 to 14.5 volts.
If it is when running at 3/4 speed, it is charging, and doing well. if it is at battery voltage, 12.6 or so it is not charging.
Bob M wiring diagrams are the real thing, look them up in the archives. Jim

Wires for the voltage regulator should not be there as this harness was supposed to be for internally regulated wiring harness. Alternator is not charging. Bob M wiring diagrams are no help as they are for an M with distributor and different starting switches...

The diagram above will do the trick.
There are two gray wires going to switches (bottom right of illustration) these are for the three wire normal 10SI Delco or Hitachi. If you ignore these exciter wires because your one wire does not need them, you will see that the remaining fat black wires from the Alt to the gauge, and from gauge to starter switch, Plus the one gray wire to the lights, are all you need. I recommend a fuse link be placed in the wire where it attaches to the starter switch.
(starter switches can be as shown, or a square push button, or a rod activated push button, or changed by an owner to almost anything. If you find the big positive wire from the battery, it will be attached on its other end to the starter switch no matter what it looks like. This is where you should attach the wire to the fuse link. This prevents a failed alternator from starting a fire. The fuse link (NAPA has them) should be about 10% higher rated than the alternator output.

There is no connection to anything on your mag at all. Voltage is never supplied to it for any reason. It is grounded to stop the tractor.

If the wiring harness you have purchased has smaller wires running from the electrical box to the alternator, ignore them, or tape them up.

Jim

I am going to add that if it still will not charge, the alternator might be the problem. Many believe in the one wire systems. I do not. In every case, they are always on. (just a little bit, but it is a drain) They also seem to have more issues with turn on speed, and pulley size. If it does not work, try the normal Hitachi, or Delco and wire as shown. Jim

Well your diagram matches how I already had it hooked up. Taped off the extra wires today and ran the tractor around a little more. Everything seemed to work fine today! Maybe I just didnt not hit a high enough RPM the other day to excite the alternator? Oh well its all working now! Thanks for your help!