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Guide to bypassing the reserve lighting unit

21K views 30 replies 15 participants last post by  Buddy 
#1 · (Edited)
If your Reserve Lighting Unit (RLU) has gone bad but your headlight filaments are still good, bypassing the RLU can keep you on the road past sundown.

Bypassing the RLU is also necessary to prevent headlight flickering when replacing the stock headlight with LED. The lower power consumption makes the RLU think the headlight is blown, causing it to send pulses of current instead of continuous power.

The procedure is easy:
1. Remove the right side cover. The RLU is a black box just under the cover, seen in the first picture held in place with two screws.
2. Disconnect the molex connector between the RLU and the main wiring harness
3. Jump the blue wire to the blue/yellow wire on the wiring harness. As seen in the second picture, that's the left and second-to-left slots on the bottom row of the connector. Be sure to use a wire that is an adequate gauge for the current you need (Too small a wire may overheat. LEDs might not need as large a wire as the stock harness).
4. Completely wrap the wiring harness's half of the connector in electrical tape to keep the jumper wire from working loose and/or shorting to something else on the bike.
5. Do not reconnect the RLU to the wiring harness. It can be removed completely in order to make room for other projects, like a R/R relocation.

Alternatively, just removing the RLU then cutting and splicing the blue and blue/yellow wires together accomplishes the same thing, but isn't as reversable if you're doing a temporary fix while waiting for a part to ship.
 

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#4 ·
Always wanted to take this thing off. If my headlight goes out.. I'll notice, and hit the high beams myself :D

Nice post
 
#9 ·
And I aint gonna be completely nude.I ain't gonna take off my cut ;)

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#10 ·
well I guess you all are gonna be disappointed cause there ain't gonna be no nudey pics tonight. Sorry but the hottest chick at the bar tonight had an Adams Apple,so their ain't no chick to run the camera.and no,selfies are outta the question.

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#11 ·
+1 for sticky

And in case anyone else runs into issues like I did after adding a led headlight, I ended up pulling the whole rlu and leaving the blue and blue/yellow jumped on the remaining plug. Tried leaving it in and it never worked for me, blue to blue/orange just locked the high beams on. The only time I can get it right was after pulling the whole rlu after getting frustrated. Low and behold everything worked fine. Has anyone else just pulled their whole rlu?
 
#12 ·
Glad it worked for you. You might be the first person to verify that this does indeed fix the headlight flicker.

Was it clear from the writeup that the RLU was not supposed to be plugged back in after doing the bypass? If that wasn't clear I'll edit the instructions.

As for jumping the blue to blue/orange ... hmm. With filament headlights, that might be an interesting route to boost the output of the underpowered stock headlight ... rewire the headlight switch to toggle between 'low' and 'both'.
 
#14 ·
@Thorn what I got from the instructions (for what it's worth) was to jump the blue and blue/yellow and then plug the rlu back in. This is doable with solder and does jump these 2 together and will show continuity with a meter. Not sure how I missed that was what I was supposed to do all along.
 
#15 ·
Instructions are only useful if people can follow them how you imagined!
I've added clarification to make it more obvious that the RLU should not be reconnected after jumping the wires. Thanks for your feedback!
 
#29 ·
Hi Mike I watched your video on removing the RLU one question I have . I noticed that when you turned on your ignition the headlight came on. I thought that the headlight when starting the bike stays off and when the bike starts the headlight comes on . Your headlight stayed on with ignition to on not yet started the engine on the bike. Did you do another mod On your head light wiring ?
 
#20 ·
Only five months late responding ...
After this mod, the headlight failure indicator light will never come on.
The high beam indicator will always come on when the toggle switch is high, even if the high filament is burned out.
 
#21 ·
I tried looking at the video but it keeps saying error and won't show.
 
#23 ·
I did this mod a long time ago. If my headlight burns out at night (and I rarely ride at night) I know to immediately switch to the other beam. I also have a toggle switch installed on the high beam, so that I can turn the headlight off and have enough power to use my electric gloves.
 
#24 ·
So if the headlight won’t turn on, nor does the warning come on, would that be a bad RLU? Would bypassing it be a way to troubleshoot it?


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#25 ·
A bad RLU could definitely cause a dead headlight with no warning light. If you bypassed it and got the headlight back it would 100% diagnose the problem as a bad RLU.
 
#26 · (Edited)
Thanks. I’ll give it a shot. I checked the filament and fuse, with no luck.

All other lights act as they should, indicator and brake lights. No warning light on the cluster, but the other lights work. Edit - okay, the blue wire mod worked, but only with the bike started.

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#27 ·
Looks like your problem isn't the RLU, and you've got some other stuff going on with the blue wire mod not behaving right. Mind starting a new thread if you need more assistance and we'll sort it out there?
 
#28 ·
You got it


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#31 ·
Thanks spockster

I figured that was what was done . I only would consider doing this mod if the internal relay went bad . I am not sure what other benefit I would get by doing the blue wire mod. I kind of prefer the headlight stay off while i am starting the motor. Is the only reason to do the blue wire mod is because of the relay going bad . Is there some other benefit to doing it

I bought a shorai lithium battery for my bike but the regular size battery did not have enough cold cranking power . I exchanged it for the 18 battery size . I had to install battery side ways so it would fit I got the battery with positive post on the left so when battery installed the positive wire was easy to reach . I did have to extend the ground wire to reach the negative post. Now the bike starts right up I have been using this same battery for six years . It never fails .
 
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