I have an 1988 Yamaha Venture XVZ1300. After a short 150 mile road trip I noticed that my head lamp and illuminated gauge display panel lights were not working. My first thought was to check the fuses of which all checked out okay. Next I removed the headlamp and checked the bulb, it tested okay as well.
I used my multimeter to check voltage from the connector going to the headlights. The voltage was very low which leads me to believe that I may have a short somewhere. Does anyone have any tips or experienced a similar problem that might help me crack this one? After taking a look at the electrical schematic I am not relishing the idea of tracing down a short.
There are a LOT of wires on that bike, and it does indeed sounds like you have a short or a bad ground.
I always start chasing wiring problems right at the battery.
I once had a hell of a hard time tracking down an electrical issue on a Venture 1300 (a 1983 model). I checked all the wiring over and over and sanded clean all the grounds. The issue ended up being the main battery ground cable itself. The connectors were solid and looked new, but the wire was shot. I eventually cut it open and found the wire to be completely corroded on the inside. Replaced it with new and everything ran perfectly.
I would imagine your issue is closer to the fuse block than the bettery, but you never know until you just tear into it and spend a couple hours scratching your head.