Hey Scott, what model , year is your machine, there is a few changes over the years, especially ones with the clutch safety switch . It really is very simple once you understand how each circuit is laid out. When I start with an unknown bike with some ghost in the machine, I find most probs are caused by corrosion,first, and PO mods second, especially if it had one of the very popular large touring fairings that required mods in the headlight and signal area.
I use a very simple test light and two jumper wires, one for hot and one for ground, just bypass the harness and connectors, then it is a process of elimination. I clean the connectors with a very small file and a can of carbon tet (contact cleaner). The bar switches will be unbelievably gunky, careful with the cleaning here. I have two horn button springs hiding out somewhere in my shop!
Here is a K8 that we gave up on and built a totally new harness, adding modern electrics.
Enjoy!
