marcaztls Posted February 10, 2014 Report Share Posted February 10, 2014 millemille I'm probably looking at you amongst others... I have a customer's bike in, and he's given me an LED tail light strip to fit to his race tail unit. It has built in indicators, of which there are two feed wires, a common earth wire and one single rear light wire. So four wires in total. My question is, can I fit a resistor to the bike's tail light feed to 'dim' the LED's and also join the bike's brake light feed to it, so the LED's function as both tail and brake? Just get brighter with the brake on... If so, what's a suitable resistor please thank you very much Link to comment Share on other sites More sharing options...
lorenzo Posted February 10, 2014 Report Share Posted February 10, 2014 If it's anything like the one I had on the 675, just ignore the indicator cables, then the whole thing'll work as a tail light. I'm confused by it just having 4 wires though, surely it's have an earth, a tail light, brake & then 2 indicators, giving 5? Link to comment Share on other sites More sharing options...
marcaztls Posted February 10, 2014 Author Report Share Posted February 10, 2014 Yep that's right, it should have five wires, then I'd just wire it up as a full replacement. The owner wants to keep the indicators function, he doesn't have others fitted, so I need to find a way to make the red LED's all work as both tail and brake. I'm hoping just a resistor will drop the tail feed down enough to dim the LED's, and then applying the brake feed to the same wire will have full brightness. It makes sense in my head...! The indicator LED's are seperate yellow ones on either side of the reds, all in one continuous strip. Link to comment Share on other sites More sharing options...
marcaztls Posted February 10, 2014 Author Report Share Posted February 10, 2014 Aha! That all makes perfect sense, thanks Mike. Gives me a good excuse to pick up a variable pot which I've always thought would be a handy thing to have too. I hadn't thought about the need for a diode though, or course... Good call. By the way, did me typing your name into the first post alert you somehow? I've wondered when I see people doing that. Thanks again. Link to comment Share on other sites More sharing options...
tomekzxr Posted February 14, 2014 Report Share Posted February 14, 2014 It will work, just test what value of resistance You need. I had same setup on prevoius bike. No need for additional diode- how would the back feed affect anything? You make just a parllel connection of the same voltage. One think I would check is the common polarity of brake/tail light on bike side, as on my current 09 R1 is postive-surprise. Then I needed to use additional relay to reverse polarity. Link to comment Share on other sites More sharing options...
marcaztls Posted February 18, 2014 Author Report Share Posted February 18, 2014 Quick update on this - works a treat. I used the variable resistor millemille posted a link to, wired it in, wanged it down to 350ohms which is a suitable difference twixt tail and brake brightness, boshed the brake feed in and perfecto. No diode needed on this. All works a treat, thanks for the help muchly. Link to comment Share on other sites More sharing options...
kaighn80 Posted February 18, 2014 Report Share Posted February 18, 2014 So now you know that you need a 350ohm resister you can take out the pot till it's needed on the next one Link to comment Share on other sites More sharing options...
jollygiant Posted February 18, 2014 Report Share Posted February 18, 2014 Linking this thread as if everything comes together I'll be wanting a small light tail light to by the summer. Link to comment Share on other sites More sharing options...
marcaztls Posted February 19, 2014 Author Report Share Posted February 19, 2014 So now you know that you need a 350ohm resister you can take out the pot till it's needed on the next one Yep, I should have added that I did just that, thanks. I ordered three of the variable resistors because they'll come in handy. Maplins sent both the variable and fixed rate ones next day, cheap as. Link to comment Share on other sites More sharing options...
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