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Aux light trigger wire on 2016+ LED lights?

Posted: Sun Aug 08, 2021 1:07 am
by Harald
Picked up a nice set of 57FA LED aux lights from advmonster to mount on the forks of my 2020 ES. These tiny lights are very bright and have both Yellowish low beam and bright white high beam options with a crisp cutoff beam pattern. I fabbed up some nice brackets to mount them on the forks and set out to do the wiring today. I can't find a suitable high beam trigger source off the bikes LED high beams! The Yellow wires at the LED headlights show 13 volts on low beam and 0 volts on high beam. No other wires to the LED modules vary. Normally this wouldn't be a problem wiring a relay for a negative trigger, but my wiring doesn't work. Both yellow and white aux lights are on continually when switching the bike from low to high beams (the yellow should always be on and the white only when high beam selected). To verify that the relay trigger is the problem, I moved the trigger wire from the bike headlight and touched it to the battery hot terminal and the aux light yields the correct response. So I'm thinking the 13 volts I'm seeing on the bikes LED light wire is current limited and won't switch the relay. Perhaps there's a relay that requires minimal current to actuate?

Anyone come up with a solution to this problem? I've searched the forum and Google with no ideas. Yeah, I could just wire up a switch to battery 12v to cycle the high beam on, but I like things to be simple and easy to operate even if it takes a lot of work to get there. LOL :lol:   A good example of that is the few hours I spent yesterday modifying the stock Yamaha trunk lock cylinder and the Givi Maxima trunk so that I can use ONE key for all the locks on my bike.   :D

Re: Aux light trigger wire on 2016+ LED lights?

Posted: Sun Aug 08, 2021 8:11 am
by raYzerman
I have read similar situations..... bottom line, can't tap in to the LED headlights. Can't remember if there was an answer... I'll see if I can stumble across it in another sandbox.
IIRCC, high beam switching is done internally in the LED headlights, and the high beam wire may carry 5V normally and cuts to zero when highs selected... ???

Re: Aux light trigger wire on 2016+ LED lights?

Posted: Sun Aug 08, 2021 3:09 pm
by raYzerman
I see your answer is in the other sandbox..... posting it here for others in the same boat.....
https://www.fjrforum.com/topic/170526-e ... ling-2016/

Re: Aux light trigger wire on 2016+ LED lights?

Posted: Sun Aug 08, 2021 7:43 pm
by Harald
raYzerman wrote: Sun Aug 08, 2021 3:09 pm I see your answer is in the other sandbox..... posting it here for others in the same boat.....
https://www.fjrforum.com/topic/170526-e ... ling-2016/
Thanks for checking. I may have to go that Skene route, although I have no need for any dimming.
There's definitely 12volts on the LED yellow wire, switching to 0 when high is selected but I've confirmed there's not enough current to cycle a normal automotive 12v relay. I found a relay that will cycle with 5ma and may give that a try.......

Re: Aux light trigger wire on 2016+ LED lights?

Posted: Tue Aug 10, 2021 1:47 am
by Harald
I found a $5 solution to my problem: A relay that will trigger off a weak signal. Works like a champ. Time will tell how reliable it is because the relay coil is powered whenever the low beam is selected due to the bike high beam trigger is either 12 volts on low or an open (not a ground). Check Amazon for a " HiLetgo 12V 1 Channel Relay Module With Optocoupler Isolation Support High or Low Level Trigger".
I'll write up details for future use by anyone trying to do the same thing when I get a minute.

Re: Aux light trigger wire on 2016+ LED lights?

Posted: Wed Feb 14, 2024 11:45 pm
by Harald
Just want to report back that this mod is still working great on my 2020 FJR. I put the relay module in a very small project box and sealed it up.
Sadly I haven't put it through the wringer like I used to when I was riding 1000 miles per month. Only 6000 miles since I installed these fork lights and custom wiring.