Finding something odd.

[cavman]

I think I am going to have to rewire my whole bike. The wiring looks like someone in the past has tried to do this and gave up and just wired what they thought they had to have. I was checking the plug for the radiator fan and found when the ignition is on I have 12.5 volts on one side and 8.6 volts on the other. This can't be right. I am sure one wire is positive and the other should be ground. I don't think I should be getting a reading of 8.6 volts. Am I wrong?