I have a new to me '77 400. Had some issues when first bought it, and am trying to resolve them. Stock wiring harness, stock electrics under left side. I have verified fully charged battery of 13.4v. I have verified with a meter that 7A light fuse is good, and showing continuity from both sides. I have removed the head light from the bucket, and confirmed continuity of GREEN.
I show no voltage when bike is not running or when engine is running, at the BLUE or WHITE male connector or at the 3 Prong connector, so I believe the problem is that the head light is not being served 12v. I have verified that the ignition switch provides 12v switched to BLACK. I have opened the left control and verified continuity of WHITE and BLUE to head light bucket. I still get no voltage at the housing with bike ON or RUNNING.
Heres the kicker: The PO removed the "PUSH BUTTON" electric start and "re-wired" the head light interrupt. Anybody got a clue as to the wiring changes he might have made and which colors are involved? I've followed the diagram as closely as possible, but don't see how/where the interrupt is configured?
