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'15 + WR250F ignition key wiring

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This will be a small write up on how to fix the issue found in this thread 


In which I and others have had trouble with battery drain issues due to the keyed ignition in the Baja Designs (and possibly other) wiring. The problem seems to lie in the kill switch putting a constant drain on the battery. You can not have the kill switch tapped into the NC contacts on the switch, as this will constantly be trying to energize the kill switch relay, resulting in a 3A constant draw on the battery. 

Member GPS Dual Sport came up with the solution but didn't document and was only describing it to me off the top of his head, as he had already sold the bike.

The objective is to kill power without constantly energizing the kill relay. In order to do this, GPS came up with turning power to the ECU on and off with the key,  in addition to the blinkers, tail light, and horn. This 12v feed comes from the Baja Designs 15A fused harness, rather than the stock. In order to do this, we have to move the headlight circuit off of the BD harness, as a it will cause a voltage drop strong enough to restart the ECU.

We must move the Hi/Lo switch power to come from the stock harness headlight wires, which will automatically only allow it to come on with the bike running.

We must also tie together the power going to the hand controls for the blinkers/horn with the ECU, and put that on the other side of the ignition key switch, so that it's powered by the BD wire harness.

Here is pictures of my BD harness up front, and where I cut and tapped into the ECU harness. 

imageproxy.php?img=&key=b3312acf975e3c54Do note that my harness will look a bit different as I removed a lot of unused connectors, and there are a few more male/female connectors than there needs to be due to boo-boos when figuring out the circuitry. 

I ran a solid red 18g wire from the front to the ECU plug and cut the red wire from the back of the plug and crimped them together. There are cleaner ways of doing this like removing the pin from the plug and putting a new wire/pin in, or possibly cutting into the wire harness further from the plug and doing it there, but I was just using things that I had and the garage and trying to keep it simple. Plus those are really tiny pins in that plug. 

That red wire ties together with the red wire going into the hand controls connector on the harness side, it becomes a different color once it's on the controls side. Also I it is hard to see in my picture. It is crimped with the red butt connector to the grey wire, as it is very short to begin with. Those two wires together are put to one side of the switch, the other side being the blue wire coming from the BD harness. This is the +12v. This SHOULD be coming out of the big square white connector, but my wire fell out of the crimped pin in the female side of the connector, so I pulled the other side out as well and just used male/female crimps.

Next you need to get your hi/lo headlight power. Cut the green and black wires out of the stock headlight connector. This is the +/- 12v. Green goes to the grey going into the connector, which turns into blue on the controls side. Black then goes to the black going out to the headlight connector. Cut and cap this black where it comes out of the white square connector.


That should be it. Your key should now turn your ECU on and off, along with your blinkers and taillight, while your headlight is only on when the bike is running. Thanks again to GPS Dual Sport for the idea.


DISCLAIMER: I ASSUME NO RESPONSIBLY IF YOU BURN UP YOUR HARNESS(ES) OR CAUSE ANY OTHER DAMAGE. Although hopefully you'll blow a fuse or two before that happens, like me.





Edited by Shleeven

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Think its the same for a 2013wr250f? Because im having the same issues. And when i was riding street my bike stayed running but lost like 50% of throttle power. Not sure if its because of this bd kit or something else, but i let my bike sit for 5min, kicked it over and the throttle power went back up to 100% it was some weird shit.

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