Tail Light warning indicator periodically lights up.

[cmyoch]

I'm perplexed by this one. I wired up a new cateye tail light utilizing my original mount. I ran a ground wire from the mounting bolt to the fender since my mount is rubber mounted. My tail light failure indicatator periodically comes on and off. I've looked back and noticed that my light is working perfectly so I know the bulb isn't blown. I have noticed though that if the light is glowing and I hit the brakes, the brake switch seems to turn the indicator off. Any ideas what this could be? Could it be a failure in the brake light switch?

 

[650Skull]

The taillight fail light is also an alternater fail light on the 78. Check your charging system

 

[pamcopete]

cmyoch,

The rear fender is not grounded. It is floating on its rubber mounts. There may be a "casual" ground due to accidental metal to metal contact of the fender to the frame, or one of the rubber mounts may be worn through, but it is not a reliable ground.

You have to run a ground wire from your new tail light all the way to the frame to get a reliable ground.

 

[cmyoch]

I'll re-wire my ground. At first I thought my charging system was the issue but I wired a voltmeter on the bike and watched it religiously. I was at a consistant charge of 14 volts. Plus, I was riding at night and I had my brights on for most of the ride without any dimming whatsoever. I'm thinking it is a ground issue now because my indicator would shut off each and every time I would hit the brake.

 

[XSLeo]

Is your new tail light bulb the same as the stock bulb. The brake light failure circuit detects the current draw to determine if the bulb ib blown. The stock bulb is 8watts on the tail light, 27 watts on the brake light. If you new bulb has a 3w/23w then the current draw is less and the failure circuit sences this as a blown bulb.
Check to see if your bulb is the right size.
Leo

 

[cmyoch]

I transferred the original bulb from the stock housing. I haven't looked at it yet but I think I need a better ground. The indicator light shuts off the second the brake switch is activated. I'll work on it this morning and see if that solves the problem.