Need UFO tail light wiring info WR400f

Just purchased the UFO rear fender for my 1999 WR400F. The stock wire colors are Blue, Black, Yellow

UFO colors Green/Wht, White, Brown

Which colors match the stock wiring?


Plug 'em in and see for yourself.

Plug 'em in and see for yourself.

I wish I could help you. I went thru the same prob. I bought some extra fuses until I got it right.

And we are not all dill heads down here in fl

And we are not all dill heads down here in fl

Screw you

Orland Rich what a jerk, why bother even posting that. I figured this was a forum that helps produce technical help. I was trying to save some hassle and time trying to wire this properly. Sure I could just start plugging stuff in and see what happens. I suppose thats what a typical monkey mechanic such as yourself might do instead of following a proper wiring diagram, and what I will do as a last cause if no one can produce the information I am seeking. However if anyone had an answer I would be thankful for some help which is what I understood these types of boards were all about is helping fellow riders through problems and sharing information. :lol:

Well, I look at this post and I see you are asking for help for something that will take all of 2 minutes to figure out for yourself. So I say "Plug 'em in and see for yourself". Sounds like a reasonable suggestion to me. Kind of like asking "I wonder what this button does?" Push it in and find out, man. Learn something. So then DRZJay400e calls me a dill head. (Not sure exactly what that means but it sounds a lot like dickhead.) And then I tell him to screw himself and you bust on me, too.

So, let me hold your tiny little hand through the process of figuring out what the wires do, because I'm afraid you might not be able to think for yourself. These wires are for lights. You can't blow a fuse by misconnecting them unless you ground them to the frame. So, let's go:

There are 3 wires. One of them is common, one is for the brake light and one is for the taillight. Got it so far?

You have two wires coming off the bike. One is common and one is hot. We'll call these WR wires.

Start the bike. Connect the two WR wires to any two wires from the UFO light.

One of two things is going to happen, either the light comes on or it doesn't.

If you get a light to come on, you know one of the two UFO wires is common and one is hot (either brake or taillight). So now you switch one of the WR wires to the third UFO wire. Does the light get brighter or dimmer? If brighter, then that is the brake light wire. If not, it's the taillight wire. If it goes out, then the wire you moved off of was the common.

If no lights come on, then the third UFO wire is common and the two are tail and brake light. Use the above elimination process to figure out brake or taillight between the two.

See that wasn't so hard. It took way longer to explain than to actually do. Everyone wants everything handed to them on a silver platter when one minute of investigation would have been all it took to figure it out, pea brain.

I didn't start out to be a jerk but you two numbnuts just irritate me.

Well part of the problem is there are no connectors on the UFO so I need to cut and splice my other wiring so I wanted it to be right the first time. The other problem is the motor is currently out of the frame so I cannot start the bike to do your simple test. Even though you still don't know the answer to my question at least in that post you attempted to share whatever knowledge you may or may not possess on the subject. I think were making progress.

Good luck. By the way, don't take any of my advice because I don't have a clue what I'm talking about.

First, If I were you, I would put either bullet or spade connectors on the wires...not only will it make connecting things easier, it will make it much easier to take off the subframe or replace the fender should you need to...

I just looked at my B-D taillight, and my son's UFO tail light with integral turn signals. Neither has the same combination of colors.

On the bike side, blue is brake light, yellow is tail light, and black is common (ground). If you don't have a hydraulic brake light switch on your bike, you can ignore the blue wire. Now, I don't have a UFO tail light, but I would guess that the white wire is common (ground) for the tail light. If you have a continuity checker or ohm meter, check for continuity between the white wire and the brown wire and white wire/green-white wire. They should both show continuity (or approx zero ohms). That will verify that the white wire is ground. If not, repeat using one of the other wires. Once you have established which wire is ground, you need to determine which wire for the running light and which is for the brake light. COnnect a 12v battery (car, motorcycle, cordless drill, whatever) across the ground and one of the other wires, then across the ground and the other wire. Whichever wire makes the brighter light is the brake light. Connect away!

Good luck!

Thank you that was very helpful and I believe I can figure it out with that information. I had planned on the bullet spades for quick disconnect as you suggested.

On the bike side, blue is brake light, yellow is tail light, and black is common (ground).

On my WR400F 2000, the yellow is brake, blue is tail light and black is ground.


And as I remember correctly, Acerbis has the same combination and Green/Wht was brake, White was tail light, Brown was ground.

But it is easy to check, take out the bulb, and check the continuity between the terminals and wires.


Hope it helps

wow. Rich in Orlando is a d*ck. If I would've seen this earlier I would've helped you for sure. I can't stand when people answer forum posts like that. If you don't want to help or answer somebody's question....don't! But don't post just to be a jerk. Sorry for people like that.

I agree this was very helpful which seems to be hard to find!!!!!

I also thought that this sight was for people to search for answers to their challenges and not get greif!!!

Here is how its done with the ufo fender and tusk hydraulic brake switch. 2000 WR400F


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