Blue wire bypass - headlight relay mod

32577 Views 57 Replies 24 Participants Last post by Mikeee15, 11 d ago

crowley1027

Discussion Starter · Mar 23, 2014 (Edited)

This guide bypasses the headlight relay, lighting your headlight when you turn the key, instead of when the engine turns.

Don't ask me about the pros/cons of this; I'm sure it will be discussed.

Video detailing the procedure at https://www.youtube.com/watch?v=C1_1MTfiJb8

On the left side of the bike remove the side cover. Unscrew the bottom screw and pull the side cover off. If you are sitting on the side of the bike, facing the side cover, pull directly toward you.

http://i16.photobucket.com/albums/b5/crowley1027/vn/IMG_20140323_061053.jpg
You will see a Palm sized black box with two connectors coming out the right side of the box. One is a smaller ten pin, one is an 8 pin.

http://i16.photobucket.com/albums/b5/crowley1027/vn/IMG_20140323_061153.jpg

Don't make the mistake I made - don't touch the ten pin connector. I pulled the blue wire from the 10 pin and moved it to the 8 pin. This is WRONG.

Pull out the 8 pin connector.

http://i16.photobucket.com/albums/b5/crowley1027/vn/IMG_20140323_061246.jpg

There is a blue wire. Pull the blue wire out of its spot (or push it from the front of the connector to reduce stress on the wires) and move it to the empty spot on the same connector.

http://i16.photobucket.com/albums/b5/crowley1027/vn/IMG_20140323_061333.jpg
http://i16.photobucket.com/albums/b5/crowley1027/vn/IMG_20140323_061559.jpg

If the spade connector pushes out as you push the connector in, just connect the plug, then push the spade connector into the empty spot to secure it.

Operation complete.

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21 - 40 of 58 Posts

Thorn

· #21 · May 24, 2018

Without looking it up, I think the blue wire mod only bypasses the relay, not the RLU.

Spockster

· #22 · May 24, 2018

Thorn said:
Without looking it up, I think the blue wire mod only bypasses the relay, not the RLU.

You're right.

There's a thread here somewhere about an RLU bypass.

magicdave2

· #23 · May 24, 2018

Ahhhhh, so maybe I didn't need to do the mod in the first place. This LED light was "supposed" to be plug and play. Comes with an inline driver that is supposed to stop error messages due to lower wattage.

Does anyone know if the OPT7 LED bulb needs either of these mods?

Thanks!
David

Spockster

· #24 · May 24, 2018 (Edited)

magicdave2 said:
Ahhhhh, so maybe I didn't need to do the mod in the first place. This LED light was "supposed" to be plug and play. Comes with an inline driver that is supposed to stop error messages due to lower wattage.

Does anyone know if the OPT7 LED bulb needs either of these mods?

Thanks!
David

http://www.vn750.com/forum/19-electrical/87625-guide-bypassing-reserve-lighting-unit-2.html

Thorn wrote this guide too.

edit : I guess this is the same one he posted earlier.

Looks like the RLU just isn't happy with the OPT7.

I would keep the blue wire mod. You have an LED headlight now, and the relays in the JB are trouble. You just bypassed one.

magicdave2

· #25 · May 25, 2018

Okay, I'll keep the blue wire mod and then do the RLU bypass as well.

What type of wire is best for the jump?

Thanks for the help everyone!

Sincerely,
David

Spockster

· #26 · May 25, 2018

magicdave2 said:
Okay, I'll keep the blue wire mod and then do the RLU bypass as well.

What type of wire is best for the jump?

Thanks for the help everyone!

Sincerely,
David

12-14ga primary wire is good.

magicdave2

· #27 · May 26, 2018

Thanks Spockster!! Have a great holiday!!

Spockster

· #28 · May 26, 2018

magicdave2 said:
Thanks Spockster!! Have a great holiday!!

You're welcome, same to you!

vulkan

· #29 · Jun 14, 2018

Vulcan Rules said:
Hey that is a good idea if a stator goes out, pull the headlight fuse and just ride in the daytime. You can do the switch mod later if you decide to replace the stator. I would guess pulling the fuse would cut the power to everything related to the head light circuit. Will have to look at a good wiring diagram, the ones I've found so far for the vulcan are terrible, small, black and white, plus blurred out.

Pretty sure its the LAW to run a headlight on your Motorcycle here in sunny Florida.So......my Stator pooped out so tried the "Battery tender" thing,was OK but really tough to figure when that battery would die...then leave you sitting/walking.Not a enjoyable way to ride!! :frown2:

Reactions: 1

warbike

· #30 · Jun 17, 2018

Did this, made going through the lights electric system much better. Plus I like it just coming on with the key and knowing the headlight is working right away.

Sent from my XT1585 using Tapatalk

magicdave2

· #31 · Jun 18, 2018 (Edited)

Got the RLU bypass done a few days back. It solved the flicker-y Headlight light on the dash! And, after the blue wire mod, the light comes on when the key turns, which is very nice. Also, the LED has a much better spread and is just brighter at night.

I also replaced my rear brake/running light with two LEDs. Changing these and the headlight to LED has really reduced the dim of lights at idle while the brake light is being activated like at a stop light.

There is a barely noticeable flicker with the new LEDs only at idle, but it's very minimal and I don't think I'm going to worry about it.

Thanks for the help guys!

Ron Ryman

· #32 · Jun 5, 2019

Vulcan Rules said:
For the Blue wire mod cons - Headlight stays on when key is turned on, which obviously takes power away from starting.

What I did was splice in a good quality mini toggle switch between the ground headlight wire inside the headlight cover, drilled a small hole in the lower head light cover to run the mini toggle switch through. The switch can then be off for starting, then easily turned on when warmed up and ready to ride. Very inexpensive easy fix to get full power for starting, after doing the Mod.

Can you explain this with wire colors and step by step instructions I did the blue wire mod and would like to install a switch?

Sent from my SM-J700T1 using Tapatalk

Spockster

· #33 · Jun 6, 2019

The ground wires on this bike are black w/yellow stripe. Ground switching is the best way to go when it's possible, no chance of it shorting out. My voltmeter is switched on the ground side.

If you get the AGM battery, the headlight staying on should be no problem.

BannedAde

· #34 · Oct 25, 2019

Hi Guys (and Gals) 👋 I’m in England and have just joined. I’ve recently replaced my stator and rectifier and suddenly have the dreaded “Headlight not working” scenario. I think a mod was done to the bike before I got it (late last year) as the headlight used to come on with the ignition switch. I can’t see the “blue wire mod” at the fuse box end though and the connector where one would expect the power to come onward from the fuse is empty, so where does it go and is it really protecting the headlight circuit????☹
My question is - is the headlight relay replaceable? And if so how? As this seems to me to be the obvious solution...
I’m no electrician, so please excuse me if the answer is staring me in the face!
Safe journeys all
Ade

Thorn

· #35 · Oct 26, 2019

Hi Ade,

After the standard blue wire mod, the headlight fuse will be unused, and the taillight fuse will provide power to the headlight.
Replacing the headlight relay requires desoldering the old component and soldering a new one back onto the circuit board. It is not a horrible procedure if you're comfortable soldering, if you can find the right component to buy.

Regarding the rest of your problems, I suggest starting a new thread specific to resolving the problems on your bike since it sounds like there's going to be a lot of investigation involved and we should try to keep the post count low on this "how-to" thread to keep things clear for future readers of the blue wire mod.

BannedAde

· #36 · Oct 26, 2019

What is the “reserve” lighting unit for?
And how do I check it’s working please?
As still baffled as to why I have power going to the blue wire from the headlight fuse, but no power at the light... 🤔
Cheers

BannedAde

· #37 · Oct 26, 2019

Thanks for your help Thorn btw 👍😁

mmart

· #38 · Oct 26, 2019

BannedAde said:
What is the “reserve” lighting unit for?
And how do I check it’s working please?
As still baffled as to why I have power going to the blue wire from the headlight fuse, but no power at the light... 🤔
Cheers

The reserve lighting unit will automatically switch from low beam to high beam if it detects a filament failure. Without you having to toggle the headlight switch. If there is any intention on going to an LED headlight, it could cause flickering because the LED bulbs do not consume as much power as the stock incandescent bulbs. It can be bypassed very simply by using a jumper across 2 pins on the connector. That mod can be easily found on here (with pics) by running a search on “RLU bypass”

Wizard

· #39 · May 13, 2021

Thorn said:
It actually moves it to a pin that is protected by the TAIL fuse, also 10 amps, so the headlight is still completely protected. You can even move the 'dash' lights (red/blue wire) to the originally empty spot (pin 17, tail-light fuse protected), and move the headlight (blue) to where the red/blue wire was. That gives you all the benefits of the mod while keeping the headlight on the headlight fuse for OCD people.

Crowley said the pros and cons would surely be discussed, but nobody discussed! Here's my take on it:

Pros:
1. Protects against a dead headlight due to headlight relay failure.
2. Your headlight comes on as soon as you turn the ignition to 'on'.
3. No wires cut means this mod is completely reversible.

Cons:
1. Since the headlight will come on when you turn the ignition to 'on', it lowers the available voltage to the starter motor.

I'm also going to recommend an additional step to the mod:

Remove the smaller, ten pin molex connector from the junction box. Using a small screwdriver, release the retaining pin on the yellow wire's blade connector (pin 9), which should be the second wire up on the back row.
DSC_0343.JPG
Cover the blade connector in shrink wrap and heat it until securely insulated.
DSC_0349.JPG
Use a small zip tie to gently but firmly secure this wire to the bundle of yellow stator wires that go to the rectifier/regulator so it doesn't wander somewhere it shouldn't.

Additional pros:
4. Protects your stator from burning out if the headlight relay coil shorts out. (the safer the better)
5. Protects the starter relay (the one outside the junction box) from the constant unregulated voltage pulses it usually gets from the stator.

There's another con to it you won't be able to jump the bike if need be cause it causes the voltage to back fire and starts heating the jumper cables I did and it didn't work so I just decided to order a new wire harness

Thorn

· #40 · May 13, 2021

Wizard said:
There's another con to it you won't be able to jump the bike if need be cause it causes the voltage to back fire and starts heating the jumper cables I did and it didn't work so I just decided to order a new wire harness

I've jumped my bike with the blue mod in place, no problem. Voltage back fire? Sounds like you might have a short in your system.

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