Farmall 100 electrical problem

My 100 was running perfectly then just quit dead, no power to anything not even lights. It was converted to 12 volt and the battery is fully charged. I have gone through the wiring and can't find any breaks and the ground is good. It has to be something I am over looking. I am open to all ideas, thanks

Well you say the battery is charged how do you know that?? One like that where I start it by hot wiring it and see if it starts. If it does start then I know the problem is from the coil back which means a bad switch or wire. If it still will not start hot wired then battery connection or other such thing is bad

I go with old's comment. I would first disconnect the battery and wire brush and sand out the terminal surfaces. A test light will find the location of the failed circuit. Jim

Old-when saying hot wire how specifically would you do that?

Jumper with a #12 wire (alligator clips are nice) from the non ground side of the battery to the coil, or to the ballast resistor if it has one. Jim

Steve706, It's a relatively simple system, so it won't be too hard for you to figure out. Seeing as you say you have NO power to anything, it rules out all the minor stuff. If you have a meter it will be a bit more informative, but even a 12V bulb on pigtails will give you solid clues.

First, check the battery at the terminals - a bulb should glow brightly, or a meter show at least 12.6V (half that if it's a 6V system). Next, move just the grounded test lead to some point on the chassis - it should show the same as on the battery itself. If it doesn't, you have a bad ground connection between the battery and chassis. If it shows good, then move the "high" side test wire to the battery stud of the starter. If it doesn't show good, you've a bad connection on that side of the battery. Not that this next step applies to the 100, but with any tractor that starts from the key switch (rather than a starter rod), if you have power at the starter stud and chassis but nothing beyond (like lights) the probable fault is in the "fuseable link" - the smaller, usually 10 AWG wire that goes from the starter stud to the ammeter and the rest of the electrical stuff on the tractor. Some of them are actually fused! Most from the 40's to 60's aren't.

Yes, battery connections can give out 'just like that', and usually, it's the positive terminal that needs the cleanup, be that the grounded or high side of the system. If the battery clamps have been replaced, there is a chance that the wire clamps have a bad connection.

Hope that helps. If not, let me know and I can walk you through a more through set of tests.

Well Worn