Strange headlight problem
Posted: Tue Jun 05, 2018 1:47 pm
Hello everyone!
I have a 1979 cb650 with a dead headlight problem. I'm already ruled out the bulb itself, so I got to checking this wiring diagram for the answer
https://imgur.com/a/6RPUmiZ
I decided to follow the path of the power starting from the ignition switch to the fuse box. Good voltage on both sides of the headlight fuse, so then I cracked opened the right controls/throttle assembly and probed where the black/red wire ends up transfers power to the blue/white wire going to the high/low switch when the starter button is free. Voltage was present all the way to the high low switch itself, so I took that apart too and found that
the blue/white wire has voltage too! I then used a little piece of wire to jump to the white or blue pads to rule out the actual moving switch (for low and high beam) and to see if it would either burn the fuse or turn on the headlight, but neither happened when bridging the pads together like the switch normally would...
So then, I thought check for continuity. The white and Blue wires each tested good going from the switch to the headlight connector, however for some reason blue had continuity on both the blue and white pads at the switch... I then checked for ground and noticed the green wire at the connector tested good to the negative terminal of the battery, but then so did the blue wire!! Meaning the blue wire has a dead short to ground? But doesn't burn the fuse? The horn is also not working on this one, if that's somehow related. Turn signals and starter work fine.
Any thoughts very appreciated!
I have a 1979 cb650 with a dead headlight problem. I'm already ruled out the bulb itself, so I got to checking this wiring diagram for the answer
https://imgur.com/a/6RPUmiZ
I decided to follow the path of the power starting from the ignition switch to the fuse box. Good voltage on both sides of the headlight fuse, so then I cracked opened the right controls/throttle assembly and probed where the black/red wire ends up transfers power to the blue/white wire going to the high/low switch when the starter button is free. Voltage was present all the way to the high low switch itself, so I took that apart too and found that
the blue/white wire has voltage too! I then used a little piece of wire to jump to the white or blue pads to rule out the actual moving switch (for low and high beam) and to see if it would either burn the fuse or turn on the headlight, but neither happened when bridging the pads together like the switch normally would...
So then, I thought check for continuity. The white and Blue wires each tested good going from the switch to the headlight connector, however for some reason blue had continuity on both the blue and white pads at the switch... I then checked for ground and noticed the green wire at the connector tested good to the negative terminal of the battery, but then so did the blue wire!! Meaning the blue wire has a dead short to ground? But doesn't burn the fuse? The horn is also not working on this one, if that's somehow related. Turn signals and starter work fine.
Any thoughts very appreciated!