Ignition Switch Troubles

drpepper1885

drpepper1885

Member
Hello. I completed the rewiring of my 1917 truck to convert it over to 1922 wiring to go with my freshly rebuilt 1922 engine. She started well and the ammeter was registering a charge on the 6 Volt, so I assumed that I was ready to hook up the headlights. The wiring kit that I go from one of the big parts houses did not have the headlight wires marked properly. Instead of including the properly marked black with green/red tracers, I guess they got sloppy and included two solid black wires.

I hooked up one of the headlights and turned the dash switch to dim. Well, to my surprise, I had a light behind by new repro switch now. It was not a light but a small electrical fire/short that fried the wire that ran from the "Bat" terminal on the ignition switch to the "Bat" post on the ammeter (electrical fires stink). I quickly turned everything off and luckily the damage was just on the one wire. I unhooked the headlights and replaced the wire and she started up again. I did not attempt to connect the headlights again.

The ammeter was an original that I cleaned up. It appeared to be working fine until I tried to turn the headlight on.

Any ideas on what caused the short when I tried to turn on the headlight? Could I have wires crossed and would it have made any difference?

Your thoughts are always appreciated.

Thanks in advance.
 
The two wires in the headlight part of the loom are supposed to be the hots for dim and bright headlights. Ground is through the housing. Switching them from one spot to the other should not have this effect. This had to be a dead short.
 
This is also a good reason to put in a FunProjects main fuse kit. Might have even saved your harness. You need to disconnect the four wires and trace for shorts on those wires. Let me know if you need info on how to do that.
 
Doug,

Thanks for the reply. When you say the "ground is though the housing," are you referring to the ignition switch? The wire that fried was the small yellow with black tracers one that ran from "Bat" on the switch to the "Bat" terminal on the ammeter. What do you mean by a "dead short"? I assume that you are referring to a situation where the ground was not correct.

Which "four wires" are you referring to? The four wires running to the headlights?

Thanks again for your help.
 
You mentioned this happened when you connected the lights. I assumed one of the four to the headlights burned. Dead short refers to battery power contacting ground directly. The headlights are grounded through the headlight housing. Do you have a correct schematic to follow when hooking up the wires? Also, there are harnesses out there that have an incorrect wire from the generator to the ammeter. These need to be checked. The wire is incorrectly a 14 gauge and should be a 12 gauge.
 
Thanks again for your help.
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