TOPIC:

There is a main fuse, then ignition switch. From the ignition switch, there is one main power wire going to a fuse block that powers everything. Since the ignition is so taxing, and the LED has low draw, I figured that I created a "load dependent" tail light circuit. This is why I was thinking that the relay may fix the problem. I will still run the meter testing, but will probably get the relay anyway.

Motor Head wrote: What is this an LED tail light assy? How's it wired, since you did your own wiring? Where is the feed for the power coming from, ignition switch, through fuse panel, to the brake switch, to the light? Then Tail is switched with the head light?
Measure the voltage where you connected the new light, using first the ground wire, then the chassis for the negative meter probe. Both Tail, and Brake. Then un-plug the brake wire from the light, then test there for power when the tail is on. Then reverse that, un-plug the Tail wire and test there when the brake is on. To see if it is back feeding. Could be a Diode issue.

I didn't do the unplugged part, but the brake side reads less than 1v (about .78v) when the tail only is on. The tail light reads battery voltage when brake is on, but I that is with it plugged into power. I will try the unplugged part next time I go out for a smoke. Hopefully it's not the light itself. I've only had it about a year and a half, so I would hate to be replacing that already!

Clutch, just when im reading this i'll ask the question now.

I have an LED stop/tail light to fit & I'm hoping to wre it like this. Banjo bolt brake light switches for front & rear brakes both wired into the same relay to activate it. The power wire will then activate the stop light when the brakes are hit?

I've read some LED stuff about resistors & its messing my head up!

750steve wrote: Clutch, just when im reading this i'll ask the question now.

I have an LED stop/tail light to fit & I'm hoping to wre it like this. Banjo bolt brake light switches for front & rear brakes both wired into the same relay to activate it. The power wire will then activate the stop light when the brakes are hit?

I've read some LED stuff about resistors & its messing my head up!

The relay should work as you described, but it shouldn't be necessary with the stock wiring. I had mine hooked up with stock wiring and it worked fine.

You can also do a Bench test, off or on the bike. With some test leads to the battery, taking the other switches and wiring out of the equation.

With the brake light wire disconnected, it still reads .78v with the taillight on. Is this indicative of a bad diode?

clutch wrote: With the brake light wire disconnected, it still reads .78v with the taillight on. Is this indicative of a bad diode?

Is this with the wire coming out of the Light assy, with the brake wire disconnected from everything?
Sure sounds like a Diode failure/ Leak. I don't know exactly what circuitry they use in the Assy, but if you can get the Assy apart to look at the circuit/ board. You can test the diodes, get a replacement for cents.
Of course each 1 of those bulbs/ LEDs is a diode.

Motor Head wrote:

clutch wrote: With the brake light wire disconnected, it still reads .78v with the taillight on. Is this indicative of a bad diode?

Is this with the wire coming out of the Light assy, with the brake wire disconnected from everything?
Sure sounds like a Diode failure/ Leak. I don't know exactly what circuitry they use in the Assy, but if you can get the Assy apart to look at the circuit/ board. You can test the diodes, get a replacement for cents.

Ok I will pull the light off sometime soon, and post a pic of what I see (I will have no clue lol). I'm searching eBay for tail lights atm to see if there is something I like better than what I have though.

So you did hook up your Old Tail/ Brake Assy and all is OK then?

The stock one? I didn't even think to try that. If I can find it, it will be a good indicator...the 1157's have been replaced with led versions.

I didn't have a chance to hunt for the stock taillight yet, but noticed when I came home from work that I had left my ignition switch in the on position for about 9 hours or so. Luckily, the headlight was off, and the run switch was off, so the only drain was from the led taillight and the Acewell computer. I plugged in the battery tender to charge it back up overnight.

I think I am going to email the company that makes my taillight and ask them about that .78v. They may have an answer for me so I don't have to start dissecting the light. LOL

I got an email from the company about the taillight today. They said the small .78v leakage is normal. I'm 99% sure the problem only occurs while the engine is running, so I'm really thinking the ignition is drawing too much power for that fuse block. I will be rewiring the ignition with a relay to see if that corrects my issue.