How do i pull 12V switched from the high beams?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

May 31, 2010
Ok before i start i have to say i know i am overlooking the obvious solution. I was tired and in a hurry and i am sure i was just missing something here. I need to pull 12V switched positive from my high beams to activate the relay on my light bar. I also have a switch in line so i can choose to have no light bar on at all. But with the switch depressed and the high beam activated the light bar will be on. I am 99.9% there. But i am missing something dumb.

So this is where i am. I HAD Slee auxiliary light harness and Slee high beam adapter in place and everything was great. Dont ask why but i pulled the Slee auxiliary harness and installed a Morimoto harness. The Morimoto is wires like every diagram you see on the Internet. The Slee is wired a little differently. The difference is that the Slee has poles 85 and 86 BOTH coming off the high beams.he Morimoto and every other diagram has one of them grounded and the other being switched 12v to activate you lights. This all good both look like they work. If i hook the wire from 86 up to my batt everything works great, the switch turn the relay and light bar on and off. So i see no problems with the new harness at all.

I still have the Slee high beam trigger harness installed. high beams work perfectly normal as always. But i have a empty plug with one red and one black wire now coming off the high beam. Perfect I thought. just hook the red positive line off the high beam into the Morimoto switched wire. It should only have power when the high beam is on.

Like i said i was tired and in a rush but looking at the multi meter i was getting 12v power on the red line comming off the Slee high beam trigger harness any time the low or highs were on. So in other words the light bar would not dim when i dimmed high beams. It will have power anytime the lows OR highs are on. I tried messing around to see if the ground was switched or something but i had to stop working and take care of other things. I went round and round in my head because it is so simple. The positive lead tot he high beams should ONLY HAVE POWER when the high beam is activated. So what am i missing? But whey does the Slee harness pull both positive and neg off of the high beam to trigger both 85 and 86 on the relay? Is there something strange about how our headlights are wired?
I believe your last statement is correct. These lights are wired odd. I attached the diagram for reference so see if that helps.

If I am reading your post correct you have power to the relay in both high and low beam. Your probably using the Red/Light Blue (R-L) or Red/White (R-W) for the switched power for your relay. From the diagram it looks like you should be using the Red/Yellow (R-Y) which should only be powered when the high beams are on.

I've not used the Slee harness so don't know why they would pull the ground from the headlights too. Should not matter since ground is ground but maybe they did it for ease of wiring?


  • 0001.pdf
    51.9 KB · Views: 108
High beams get their +12v from the same relay/fuse/circuits as the low beams, but use a different - side.. it is switched/provided by the red/yellow wire in the high-beam switch.
Here’s a quote @bloc gave me when I was troubleshooting an issue. Perhaps it helps.
I want to say the headlights are essentially a positive ground. On the phone ATM, but there's some backward thinking in the headlights.

I'll check back later/tomorrow, but seems there's some 180* out stuff that makes the headlights such a bone of contention/issues, and IIRC that was it - it essentially flips polarity but w/o running back to my EWD, can't say ATM.

Sometimes diodes fix the issue, I'll look back later if still an open question.
I think you guys are on to something . I was thinking maybe they are a switched ground or something. On the harness as it is set up not pole 86 on the relay and the light bar both go to ground or battery. That is just like every other diagram you see. I think i am going to change it to mimic the slee set up. I am going to run both wires to the from the head light to the relays in to 85 and 86. The positive through the switch is all ready that way. I am just going to run the neg from the height directly into the relay and see if that fixes it.
Ok, i figured this out. Well i cant say i figured it out because i still dont really know why the high beams are like they are. But this is how the relay needs to be wired. 12v+ from batt in to pole 30, 12v+ out to light bar from 87. Then both 85 and 86 need to come from high beam. The little Slee high beam harness is great and i think only $6. If you want an additional switch to run high beams WITHOUT the light bar then add it into one of the wires going to 85or 86. I use the + side. Dont know if it matters.
Last edited:

Users who are viewing this thread

Top Bottom