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Headlight Wiring Help

589 Views 7 Replies 5 Participants Last post by  Trillian
Hey all
2013 cbr500r

Hoping to find some people with expertise in the electrical field, forgive my ignorance as I’m a beginner at this

long story short, aftermarket headlights both shorted out one day, found the ground wire that had an open circuit, cut off and recrimped new connector for the ground prong for the h4 bulb. I believe the original reason the ground wire melted was one connector from relay was loose (bought identical replacement and planning on glueing back together like previous owner), (before and after)
Automotive tire Automotive fuel system Motor vehicle Automotive design Automotive exterior
Hood Motor vehicle Automotive tire Automotive design Automotive lighting

google tells me (in my case yellow=low white=high and black ground/neutral position) for h4 prongs… is what I did the right positioning?
Automotive tire Automotive lighting Gas Electrical wiring Cable

Lastly both headlight bulbs have the same the wires like the picture above, do I need to connect up the highbeam bulb yellow wire to the (black wire) power if all I need is the highbeam? (Black wire is constant voltage, assuming it’s the low beam)
Bag Sportswear Personal protective equipment Electric blue Font

Before I pulled apart the wires and relay, when I switch the highbeam on, voltage shows lowbeam goes to 0v to save current, and guessing the highbeam powers both? Now when I switch highbeam the voltage doesnt Go to 0, whys that?

thanks in advance, any help is appreciated


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From the 2013 factory service manual

There is an electrical cable that runs from the bike's main electrical harness to a 4 wire connector in the headlight area. This connector carries power for the two headlights and the small "position" light.
The aftermarket installation probably plugs into this connector or crimps to its wires.

This factory cable has the following colors
green = ground (goes to all three bulb sockets)
blue = high beam
white = low beam
pink/blue = position light

The blue wire goes back to the headlight relay and the high-beam dash light.

The factory headlight relay does not disconnect the low beam when it activates the high beam.

If you know the model and brand of the headlight conversion, perhaps someone else has used it and can offer specific advice.

Since a wire melted, check the rating of the physical fuse in the fuse box. Someone may have installed a way-too-big rated fuse to "fix" occasional fuse blowing due to the bad wiring you mention.
Thanks for the reply, looking at the wiring diagram I guess the 3 wires on both headlights are aftermarket, got me so confused since the diagram only shows 2 on each light… I’ve also heard that the h4 bulbs are dual filament and not sure how that would affect the low and high beams, before the headlights stopped working low beam would always be on and headlight+lows would both be on when highbeams engaged (like most motorcycle :0) along with that I was wondering what one random wire was doing (no power going through it either) might be my position light that he disconnected

I double checked the fuses like you said and the only thing changed was my taillight fuse which are 15a instead of 7.5a which sounds fine since it’s got aftermarket tail tidy and previously no issues there just my headlight area.
A ground plug usually does not melt since the power is on the positive/battery plug.
Maybe the bulb gets to hot. Do I understand this is NOT the factory setup?
And when you say you only need high beam , I suggest you rethink that.
Both low and high beams are useful.
And since you're there do it right.
Thanks for the reply,,
sorry worded it terribly, I meant the wires for the highbeam, before it stopped working there were 3 wires (low, high and ground) connected to the 3 prongs H4 bulb x2 (for both headlights) since the highbeam is oinly meant to come on when I flick highbeam switch (which the white wire is), I was wondering whether I need to reconnect the lowbeam as the 2nd prong??

Appeciate the help :)
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Note that we don't know how this "conversion" is supposed to work. It's whole point is that it is different from the stock system. somehow "better" (or not).

I suggest you try to find someone local to help.

If nothing else, you could remove the entire conversion (which might include the 3 pin bulb sockets?), buy the stock Honda parts + correct bulbs, put them in the bike, and have a working headlight system. One we could compare with our bikes if there is a problem.

There are online sellers of Honda OEM parts who have better prices than a local dealer. They show the factory part diagrams so you can order the correct parts.
Yeah fair point, seems like it wasn’t a complete amateur like myself but it does seem like a meh job… managed to make the headlights work but only issue I’m facing now are that the bulbs smoke after like 5-10 seconds
I recharged the battery and the voltage reads around 12.3-13v at the bulbs so it’s not like it’s getting excessive voltage, maybe the bulbs got damaged from me previously short circuiting it?
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