Truck Stop Trailer Light mod - for LED Undertails

[thebbbusa]

Mototek tail lights and aftermarket tail lights in general have all been sub-par when it comes to light output during the day. None have been DOT legal but we still do it…we like the look.

For quite some time now, I’ve been searching for a replacement for my LED tail lights…finally, I came up with a solution.

So I passed a tractor trailer the other day, and it dawned on me. The lenses on some trailer marker lights are 2†round…same as Mototek. I headed to my local (NOT!) truck stop, the one way out on the highway that actually has big truck parts. Found this….a 2†beehive style light. It was perfect, and here’s how you make it work.

First thing you will notice is that the bulb in there isn’t very bright, but it doesn’t matter, we’re cutting that out.

With the backing cut out as above, you can pop off your Mototek lens and using the mounting screws, you can securely fasten the lens to the housing.

The next two pics show the difference between the Mototek lens and the trailer marker lens. Pretty cool huh?

 

[thebbbusa]

My project didn’t stop there. The lights were significantly brighter, but I wanted blazing bright. I ordered the 48 LED upgrade kit from bikeeffects.com and went to work.

To do the 48 LED upgrade you need to remove the old housing from the bike, and replace it with the new one. Pretty simple. Then if you want the beehive lens, you will have to remove ALL of the white plastic from this picture:

Fortunately the beehive lens is a snug fit, and will snap snugly into the Mototek housing without using screws. After getting them installed, I was surprised to see the difference in brightness. In fact this picture was taken from about 5 feet away, WITH A FLASH!

No flash:

Before with old LED no flash and dark room

After:

 

[thebbbusa]

I stood back and admired my work…then came up with one last idea…to make the rear tail lights blink with the turn signals. To do this you need to purchase a 12VDC relay that has a single pole and dual throw. Most autoparts stores carry these, but no one will know what you are talking about. From what I hear the type that I used are commonly used on fuel pumps. Anyhow, the best thing I can tell you is I got mine at Advance Auto Parts:

PartsAmerica.com

Looking at the picture above you will using the 85 and 86 poles, and the 30 and 87a poles.

Find the ground wire to your rear tail lights, it could be any color since there are many different manufacturers for undertail lights. Easiest way is to figure out which wire makes the tail lights go out. The other two will be running and brake. Once you find the ground you need to cut that, and add two female spade connectors to the ends. This these will attach to the 30 and 87A poles on the relay. 87A is the normally closed circuit which allows normal activation of the lights.

Your situation may vary, but you need to now run the turn signal wires to the relay. You can either splice into the signal wires, or use what you have, if you had two sets of signals like me. If you only have one set of signals on your undertail, you need to get inline taps so your signals will still work. After you have the taps, add female spade connectors to the 85 and 86 poles. Wiring in this manner will cut the open (cut) the ground circuit when the blinker activates. If it doesn’t activate try switching the poles, it may be a polarity issue. Once you’re done you can use double sided tape to fix the relays to the tail as shown.

If everything is wired correctly it should function like this:

http://s110.photobucket.com/player....in/Tail light mod/MVI_5927.flv&fs=1&os=1&ap=1

and

http://s110.photobucket.com/player....in/Tail light mod/MVI_5928.flv&fs=1&os=1&ap=1

The taillight mod will work for anyone with a two bulb taillight.

Here’s an express version of this write up:

http://s110.photobucket.com/remix/p...name=stream110.photobucket.com&fs=1&os=1&ap=1

 

[thebbbusa]

I really like the look of the new lenses, you don't see them everyday. And they kinda look like rocket boosters, LOL

Hope this helps someone, or at least generates some ideas for improved lighting on aftermarket undertails.

 

[thebbbusa]

I forgot about costs.

Relays are about $10ea
48 LEDs with housings are about $70 for the pair
Truck trailer marker lights are about $6

 

[ThrlSkr]

Absolutely HOT!!! Thanks for posting this I want to do a tail/fender mod so bad. Cannot do it without giving up my racks/luggage though. . .

 

[runeight]

Very well thought out. Looks great.

r8

 

[Ezduzit]

Nice work!

 

[twotonevert]

That is freakin awesome, very well done my friend!

 

[Rhythm]

Before the mod I could barely see your rear lights when riding behind you, now I'm afraid I'll be blinded by the upgrade.

Nice job B.

 

[re2ned]

Freaking awesome. I can't wait to see this. Erzebet will love it (if I can ever find a cheap Mototek somewhere).

Rythm I never knew you to be much of a follower...

 

[mrninja9]

wow rythm is still aorund

 

[Wallie]

Great work

 

[06 Limited Edition]

Wow looks great....

 

[Super Trucker]

Just a little note, most truck stops have a huge mark up on truck parts. If you can look in the phone book and find a local truck parts shop you will save a few bucks.

That does look great

 

[thebbbusa]

Just a little note, most truck stops have a huge mark up on truck parts. If you can look in the phone book and find a local truck parts shop you will save a few bucks.

That does look great

I got the lights for about $6ea...not too bad.

 

[cipher5791]

Looks good bro.

 

[riccoh]

bbusa ... this is a really good and easy mod.. and it follows the body lines,,,, i just did mine and love them.... thanks again for the pics...

 

[thebbbusa]

bbusa ... this is a really good and easy mod.. and it follows the body lines,,,, i just did mine and love them.... thanks again for the pics...

Great to hear!

 

[boazalmighty]

umm, i think i might be doing this