What's wrong with my schematic?

[GGRider01]

I'm using a cheap aftermarket headlight switch and thought I could use it to kill all components on the bike. I tried running the LED brake/running light down stream of the headlight.

Take a look at my crappy schematic. With this setup the headlight is the only component that wouldn't light up.

I got everything working by abandoning this schematic, but the horn sputters when the headlight is on.. Guess I can live with it.

[jostby]

Your running the headlight and brake/tail light in series. You need to run it in parallel. Pull brake/tail light power before it goes to the headlight. Not from the ground side.

[GGRider01]

That's what I ended up with. I guess I just can't wrap my head around why it doesn't work. Is the fact that the rear light is LED any part of why?

Also, I googled more on the sputtering horn issue and it seems a horn relay comes up quite a bit. Not sure I want to mess with it any time soon.. so many wires as it is. Somehow all the components sharing a ground with the horn is causing some issue.

Here's the current setup. It's a lot more chaotic looking on the bike at the moment...

The headlight switch required more modification than I wanted to do to use it as a full off switch. The stock GG switch isn't quite as simple and requires the grip to be removed to install.

[jostby]

2nd schematic is more what it should be as long as the tail/brake has it's own separate ground after the turn lights. If the horn is hooked up as shown in schematic 1, the other wiring shouldn't be affecting it so maybe the relay as you suggest. My European trials bike horns always sounded kind of scratchy/sputter. (Aprilia and Fantic)

[Neil E.]

As mentioned your tail/brake light needs a separate ground. Your horn should work fine off a basic button. 12VDC to the button goes out to the horn when pressed. Other horn wire to ground. I've had great luck with the compact horn from Sickass Racing, #23-042 (105DB, 1.5A draw). It's a 2 wire horn not marked for polarity. Does your horn work OK using a car battery? Maybe your horn is too large for the bike battery.

What handlebar switch are you using? The stock Leonelli switch is not the greatest. A breakdown of the switch internals would help to see how you have things connected.

[GGRider01]

The horn sorted itself out, somehow. The wiring is now cleaned up and organized, and don't see anything where it could have been grounding intermittently. I went to show my dad what it was doing and put the 1/4 inch spade on the ground side and it works perfectly. I had it disconnected in case something funny was going on. Maybe just a loose connection before.

The above schematic was just thrown together quickly, the brake/running light grounds to the battery separately of the blinkers, which ground the relay first then to the battery.