Often when working on a modified truck(yours is converted to 12 Volt so modified) Things get lost that matter.
1, There is a fuse block: 2 of them. Stop lights, and head lights.
2, the wire from the key switch to the coil(+) needs to go to a ballast resistor, or, a 12 Volt(internal Ballast resisted) coil.
3, The points must be clean and make a good connection. They must be properly gapped.
4 the horn terminal...is often a relay. It is mounted on the Regulator in many cases.
No I am not attempting to be a hard a$$. I just need to know what the issues are. The above post, with the volts test points open and then closed is good advise. The concern is a 6 Volt coil and no ballast resistor will be a problem. A 12 Volt internal resisted coil will not. There are ways to find out if the coil is working. Again the above post the suggested opening and closing the points is good. You should have a spark when the points open. If the key is on. For those times when a lot of tools are not available, A finger nail will work to pop the points open. If a feeler gauge is not available, a matchbook cover will get the point gap close. If the coil is a 6 Volt unit, it will get hot, and quit after a while. If the coil is a 12 Volt coil and you put a ballast resistor in line with it, well the spark if it works will be weak. A 6 Volt coil will be close to 1.5 Ohms across the + and - connections. A 12 Volt coil will be close to 3 Ohms across the + to - connections. The arithmetic works out to about 4 Amps at the points. if the coil is matched to the Volts. So a 1.5 Ohm ballast resistor will work for a 6 Volt coil in a 12 Volt system. If you use the same resistor in line with a 12 Volt coil, then the current at the points is too low and the coil will not provide a spark. So it matters.
Last edited by Steve_H; Wed Dec 02 2015 01:40 AM.