Headlight electrical grimlin

[dirtrider0129]

I bought a 2003 DE 250 last week. the bike runs fine, but the headlight doesn't work. The previous owner said it didn't work, but he didn't have it hooked up so I couldn't see for myself. there are 3 sets of wires behind the headlight, a yellow and white, a yellow and purple, and a purple and yellow with green. I've tired to search this forum to see the purpose of each wire and the only helpful thing I have found was the electrical schematic on headlight and horn tech article. I saw that the yellow wire was the hot wire so I hooked a multimeter up to it and a ground to see what kind of voltage I was getting. I started the bike and the multimeter only read .4 volts at idle and about 1 volt when giving the bike some gas. I checked all of the connections and everything was tight. What could be wrong. I'm assuming that the ignition is good as the bike still runs, so that only leaves the regulator to be at fault. Is there some test to see if the voltage regulator is bad or am I going about this whole situation all wrong?

[MattR]

I'm not familiar with the yellow/white and yellow/purple wire combinations. Am I understanding you correctly that these are yellow wires with a stripe (white or purple)?

A solid white wire usually goes from the headlight lowbeam terminal to the headlight switch. The yellow with green stripe is the ground wire. A solid purple wire is typically hooked up to the headlight switch and provides power to the rear tail light.

You could momentarily bypass any headlight switch (if applicable), but connecting the solid yellow wire to the headlight low or high beam terminal. Then, connect the wire having yellow with green stripe to the common ground terminal of the headlight. This would make the headlight always on, but at least you would verify if the yellow (hot) wire and ground wire are completing the circuit properly.

Let us know how it goes.

[dirtrider0129]

I didn't write that out very clearly. There are 3 sets of 2 wires. the first set consists of one yellow wire and one white wire. The second set consists of one yellow wire and one purple wire. The third set consists of one purple wire and one yellow with green wire. There is no switch on the handlebars for the headlight. when I bought the bike, all of the wires were bundled up and taped to the frame. The actual headlight assembly itself is melted and can not be used again (the previous owner left it on to pass tech inspection ). so If I understand what you said, I can take a multimeter and connect one lead to the yellow wire and the other lead to the yellow with green wire and I should read around 12 volts?

[MattR]

OK, those colors sound better. You are correct... connect the voltmeter to the yellow (+) and yellow with green stripe (-) and see what voltage you get.

You could also pick up a car's headlight bulb and connect the wires to it. I would be crude but it would give you a "visual" strength of what the bike's output is while idling and reving the engine.

[dirtrider0129]

cool, thanks

[dirtrider0129]

OK, I finally got some time to do the test. I hooked up the yellow and yellow w/ green wire to a multimeter. started up the bike and it only read 1 volt at idle and about 2 volts with the bike reved up. I know that's not right, but what could cause this? The only thing that I can think of is the voltage regulator. Any help would be appreciated.

[jostby]

isn't this an ac system (rather than dc?). I have never had to do any repairs to mine so have never tested it but seems I remember people talking about converting to dc. Have you used the ohmeter to test the bulb? FWIW, my bike has a simple toggle switch mounted on one of the webs on the back side of the number plate for on/off. It's a nice out of the way spot. Good luck.

[dirtrider0129]

Originally Posted by jostby

isn't this an ac system (rather than dc?)

....ya.... well that solved the problem. I was checking voltage using the DC settings on the multimeter. just checked using the AC settings and the voltage at idle was 12.2 and reved up it was 12.5 Thanks for your help.

[MattR]

Jeff, thanks for pointing out the DC vs. AC issue.

I forgot to mention that the circuit is AC. The volt regulator is there to prevent the "spikes" is the AC voltage.

[Ned]

I'm in a similar boat here with a DE200 (2k2 ignition) with a few bundles of similarly colored wire that have the headlight terminals and 12+VAC coming through the line..


< dumb question alert >
Will this light work on the AC? Or do I need a special bulb?

edit: oops, forgot to mention this light is a basic off-the-shelf Acerbis 12v 35W CE/DOT DHH

<skip the dumb question>
light's hooked up and working. time to get the DPDT switch and horn hookled up a la MattR's approach