I need to replace the amp gauge on my 800 ford, but I am Mr. Potato Head when it comes to electrical stuff. I would like to request someone draw me a simple diagram of how the wires are hooked up. I've attached two photos to show how the old one was wired, but it didn't work with the new gauge.
"L" is Load. "B" is Battery. Hook it up the same as the old ammeter. The "whatzit" connection is probably for instrument lighting when the lights are on.
Your alternator looks to be old. I would take it to an auto parts store and get it checked out.
If you can't get it to work.... Check the wiring. The heavy wire from the starter solenoid (battery terminal) to the ammeter goes to the "B" terminal on the ammeter. The wire from the other side of the ammeter ("L" terminal) should go to the terminal block. From there ALL electrical loads should come out the other side of the terminal block.
The basic principle is that all electrical loads other than the starter are channeled through the ammeter in this way. Then you branch out from the terminal block.
Note that the headlights are not run through the ignition switch - too much current draw - may damage the switch.
Your tractor is a 12V conversion. Should be negative ground. It was originally a 6V positive ground system.