Today I worked on an Arctic Cat ATV. The owner towed it down to my place and I actually worked on it outside since the weather was ok and the shop had other things in it.
When I got the vehicle none of the electric system was working. The battery checked out fine at 12.4 volts. A modern ATV like this has about 6 fuses and they all check out good. I finally traced the problem down to a corroded wire leading to the ignition switch. The wire actually corroded away and broke off right where it went into the plug for the switch.
Once I located the problem it was a simple job to solder a new wire between the plug and the main wire harness.