Motorcycle Repair: issue on 86 yamaha xv700, wiring harness, backlight

Question
On a 1986 Yamaha XV700...Backlight for instruments wont come on as well as headlight. however headlight and backlights has come on randomly for few seconds. Also have confirmed bulb is fine with another bulb. Suggestions? we took the seat off and it came on randomly then shut off when we turned the bike on.

Answer
You have a short to ground somewhere. Look at the entire wiring harness and look for any chafed or broken wires. Look for spots in the wiring cover that are worn through. Check all your connections and your frame grounds. The way you explained it look around the area where the seat goes on the bike. Let me know what ya come up with. Thanks