Rostra Cruise and after market LED tail light----heads up

[DonB]

Just wanted to post a heads up info

I am installing a Rostra Cruise on my C14 and have gone through a mess trying to get the final check out to come out right.
the first mod I did to my C14 was an aftermarket bright LED tail light. like this one
http://www.ebay.com/itm/08-10-Concours-14-LED-CLEAR-Taillight-Tail-Signal-Light-/190552492897?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item2c5dd04b61

then several mods later I decided to install a Cruise control. well I wired up the brake relay per Brian's info located here
http://www.murphskits.com/catalog/docs/Rostra%20install.htm
I could not get the relay to click every time I would hit the brake. It would click one time when I hit the brake and then would not ever click again. took me a while to notice that it would click a second time when I shut the key off
? wth
so after email with Brian and Ralph and scratching my head for a while, I got a volt meter out and checked the blue wire for the bike brake.
put the brake on 12+ volts good deal
release the brake 4.3 volts on the blue wire......hmm what the heck???
after a while I got to thinking about the after market brake light I had installed back when.
I wonder???
so I removed the bright ebay tail light and put the oem tail light back on and BINGO
relay clicks each time I hit the brake.
just trying to give a heads up in case someone else get's to the point where I was at pulling my hair out because I could not figure out what the hell was going on

[ljcorby]

I had a similar issue with another eBay tail light when trying to wire up my Givi E55NT Tech Admore light kit?  the aftermarket tail light caused all kinds of issues with the Admore lights, but when I put the OEM tail light back on, Bingo for me too.  All is working.

[B.D.F.]

We ran into that with JamminJere way back in the olden' days when he tried to wire up the brake lights on a top box. The brake lights would not work correctly. The problem was his aftermarket tail light which was back- feeding the brake light circuit. A diode cures the problem and it is surprising that the mfg. didn't install one in the light in the first place.

Brian

Just wanted to post a heads up info

I am installing a Rostra Cruise on my C14 and have gone through a mess trying to get the final check out to come out right.
the first mod I did to my C14 was an aftermarket bright LED tail light. like this one
http://www.ebay.com/itm/08-10-Concours-14-LED-CLEAR-Taillight-Tail-Signal-Light-/190552492897?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item2c5dd04b61

then several mods later I decided to install a Cruise control. well I wired up the brake relay per Brian's info located here
http://www.murphskits.com/catalog/docs/Rostra%20install.htm
I could not get the relay to click every time I would hit the brake. It would click one time when I hit the brake and then would not ever click again. took me a while to notice that it would click a second time when I shut the key off
? wth
so after email with Brian and Ralph and scratching my head for a while, I got a volt meter out and checked the blue wire for the bike brake.
put the brake on 12+ volts good deal
release the brake 4.3 volts on the blue wire......hmm what the heck???
after a while I got to thinking about the after market brake light I had installed back when.
I wonder???
so I removed the bright ebay tail light and put the oem tail light back on and BINGO
relay clicks each time I hit the brake.
just trying to give a heads up in case someone else get's to the point where I was at pulling my hair out because I could not figure out what the hell was going on

[ljcorby]

What is this diode you speak of and how do you wire it up?  Can you provide some details?  I do really like the aftermarket tail light but not enough to sacrifice not using the Admore kit on Givi case.  Thanks in advance.

We ran into that with JamminJere way back in the olden' days when he tried to wire up the brake lights on a top box. The brake lights would not work correctly. The problem was his aftermarket tail light which was back- feeding the brake light circuit. A diode cures the problem and it is surprising that the mfg. didn't install one in the light in the first place.

Brian

[B.D.F.]

Buy a small (3 amp) diode from Radio Shack and put it in series with the brake light wire. The direction of the diode must be such that current can flow into the light but not back out of it. Put the diode in-between the taillight and the rest of any wiring; don't tap into the brake light wire <behind> the diode or the total effort will be wasted.

If you do put the diode in the wrong way, nothing bad will happen but the brake light will not work. Turn it around and all will be well.

Again, it is pretty amazing that the mfg. of the taillight did not do this on the internal circuitry but apparently they did not and this needs to be cleaned up if the taillight is used with any other electrical devices.

Brian

What is this diode you speak of and how do you wire it up?  Can you provide some details?  I do really like the aftermarket tail light but not enough to sacrifice not using the Admore kit on Givi case.  Thanks in advance.

[ljcorby]

Thanks for the information.  Just to confirm, should I do this just on the brake light wire, or all 3 wires coming from the aftermarket light?  Should I also do this on the 2 blinker wires coming from the light as well?

[B.D.F.]

Only the brake light should be necessary. The tail lights are always powered up (when the ign. is on) so that will not be a problem.

Brian

Thanks for the information.  Just to confirm, should I do this just on the brake light wire, or all 3 wires coming from the aftermarket light?  Should I also do this on the 2 blinker wires coming from the light as well?

[ljcorby]

great, thanks.  Will give this a shot and will report the outcome.

[DonB]

We have lift off. 
I installed a Diode and now have the Bright LED tail light installed again and the relay works
BINGO
 
thanks to all for the help

[maxtog]

Buy a small (3 amp) diode from Radio Shack and put it in series with the brake light wire. The direction of the diode must be such that current can flow into the light but not back out of it. Put the diode in-between the taillight and the rest of any wiring; don't tap into the brake light wire <behind> the diode or the total effort will be wasted.

Since LED's *are* diodes, it is strange it should be needed at all.  Perhaps they are using some transformer circuit or something.

[maxtog]

We have lift off.  I installed a Diode and now have the Bright LED tail light installed again and the relay works
BINGO
 
thanks to all for the help

Brian is a fountain of useful info

[martin_14]

Brian is a fountain of useful info

and other stuff... 

[ljcorby]

DonB, can you confirm exactly how you installed the diode?  I picked one up yesterday evening but won't have a chance to install it until tomorrow.  Thanks.

We have lift off. 
I installed a Diode and now have the Bright LED tail light installed again and the relay works
BINGO
 
thanks to all for the help

[DonB]

DonB, can you confirm exactly how you installed the diode?  I picked one up yesterday evening but won't have a chance to install it until tomorrow.  Thanks.

on the diode there was a band around one end. I put this end toward the tail light. I split the coating around the wires back close to the tail light and pulled out the wire (mine was green) and cut a piece of wire out and replaced the removed wire with the diode. then put shrink tube and tape around it all

[ljcorby]

Thanks, so you just used one on the brake light wire, or did you use more?

[DonB]

Thanks, so you just used one on the brake light wire, or did you use more?

just one
on the brake light wire

[ljcorby]

Excellent, thank you so much.  Will let you all know how turns out with my issue.

[ljcorby]

Ok, installed the 3 amp diode I picked up from Radio Shack on the brake wire close to the aftermarket tail light, and everything is working now.  This is great.  I also wired up the blinkers in the aftermarket tail light and I think it looks and works great.  Will try to post a video of then in a little while.  Thanks.

[ljcorby]

Ok, here is a link to the video....hope this works....enjoy.

http://s167.photobucket.com/albums/u149/ljcorby/2010%20Concours%2014%20ABS/?action=view&current=GiviCasewithLights5.mp4

[ZG]