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LED indicators - please tell me I'm not that stoopid...

Discussion in 'Modifications and Projects' started by DarkHorse, Jul 9, 2009.

  1. I have a stoopid question and want to know that I'm not missing anything completely farken obvious...

    I bought some Oxford LED indicators today, and went to install them when I got home (yes, I know what time it is) - plugged them up on the front with supplied resistors, went to test and no joy. Rear still working, stock unit works straight off stock wiring AND off resistor outputs. Multimeter for continuity over new indicator wires and nothing.

    So it has to be the new lights, right? I have to have continuity for them to work, and if originals work off resistors they are OK...

    I'm not that dumb, am I?

    Will be taking the units and my multimeter back to the shop in the morning, but don't want to go in spewing flames if I've done something completely idiotic...

    How/why could a brand new set of indicators (tested both units) designed to survive the rigours of being installed on a bike be DOA? They are sealed for life too, so no chance of getting in and sussing out details.
  2. You haven't mentioned whether you checked this, but LEDs are polarity sensitive. The wires are usually coloured so the darker one (black/dark blue) are the negative, and the lighter colour (red/orange) is the positive colour. Did it come with instructions? Did you read those instructions?

    If you did get the polarity right, and they didn't work, it is possible that they are non-functioning, so you can take it back and ask for an exchange.
  3. Thanks mate,

    Wires were red and black at the unit, red and black at the resistor and red and black from the bike. The instructions consisted of a very basic diagram which showed what I have described above. While I can't be 100% sure that the bike wiring hasn't been f*cked with, I'd say the likelihood was pretty small. I think I did try it reversed just in case anyway, but not sure.

    Polarity aside, I should still get continuity in either direction, shouldn't I? (I get none either way around.)


    I put a 9V battery across the wires and they lit up - both with and without the resistor inline.

    So now it has to be something about the quality/quantity of power from the bike? But the stockers work fine, while the LEDs do nothing with or without the resistor...

    Now even more confused.
  4. wires connected the correct way? some circuits only flow current a certain direction.
  5. Thanks Thera,

    Like I said I'm pretty sure I did check them with wires reversed, but wires from bike and all those on lights and resistors are red or black, so pretty idiot proof.

    There has been some playing with the wiring on my bike, so I can't say categorically that the stock wiring is as it should be. I'll check again when I can.
  6. Have you got a multimeter? That is one thing that you should have before doing any wiring modifications.

    LEDs will not work if they are plugged in the wrong direction, try it on the 9V battery ;)

    Next silly question time. Are you trying the indicators with the bike key switch ON? Checked all your fuses?

    My troubleshooting abilities over the internet stops around here, it's better to get someone who knows electrical stuff to do it for you :p
  7. Thanks Mekros,

    I have a cheap $20 meter, been enough to establish a connection, continuity, measure battery voltage etc. I have now borrowed a good one from a mate at work to check the power supplied from the bike (the cheaper doesn't cope well with a constantly varying current.) Also had a chat to an electronics gun at work who explained the continuity problem with diodes to me, so I'm over that.

    And yes, the bike was switched on (not running) and I tested the system at every stage with the stock indicator, which worked fine every time. :roll: :LOL:

    My best guess now is that the bikes wires are reversed somewhere between the switch/relay and the indicator terminals, so will check that again when I get the chance. Which leads to another question - does the polarity matter before the supplied resistor, or just what's supplied to the light itself?

    Anyhoo, probably be Monday before I get to work on it again.
  8. A plain jane resistor does not care about the way it is hooked up.

    If for some strange reason or another you have a smart or fault resistor, the direction will matter. If you can get to the terminals, I'd measure the resistance of the resistor in both directions and see if it makes a difference.

    Again, without knowing the units that you are trying to hook up, I can't say what will be polarity sensitive. A quick check with your (good) multimeter will tell you the +ve and -ve wires.

    edit: more thoughts

    If you believe that the polraity of the wires has been reveresed at one stage, there would be other issues with the bike (like not switching on for starters).
  9. ive read in another forum the someone tried replacing thier indicators with LEDs too. they said that the new ones stayed lit and didnt flash. not sure if this applies to you.

    the response was that the flasher needs to be replaced to handle the LEDs.

    dont know if this will help but just thought ide throw it in there.
  10. Not sure if this is the OPs problem, but my memory of basic electronics from high school 20years ago is that a Diodes job is to only allow current to flow in one direction... with an LED (light emitting diode) they light up if the power is flowing in the right direction.

    Flashing... Light Bulbs use a significant amount of power, LEDs use fluck all... replacing bulbs with LEDs will usually make the Flasher Can flash the indicators very fast... I assume that is why there is a resistor in series, to create an extra 'drain' on the circuit... Unless the LEDs are 9V, not 12V, which might explain why the OP tested with a 9V battery...

  11. threw it in there to see if anyone would agree or disagree with me. havent tried this personally so i dont know.
    just thought it might be applicable somehow.
  12. SUCCESS!!!!!

    So, to clear the situation up for anyone reading this in the future:

    The indicators came supplied with resistors so that the load matched the stock indicators, removing the problem of fast flashing, and negating the need for a replacement relay. They are meant to be completely plug and play.

    I was replacing the front indicators because I had broken one, so it was that one that I tried to replace first. The stock indicator was still working, the plastic casing was just damaged. So I knew that there was power being supplied to the wires.

    I removed the fairing, removed the stock indicator, and tried the replacement indicators (just touching wires together to start with.) With the red wire from the indicator connected to the red wire of the resistor connected to the red wire from the bike, and the black wires connected the same way. Nothing, using either one of the pair.

    Next, in order the try to isolate the problem I retried the stock indicator directly to the bike wires. It worked. I then tried the stock indicators with the resistor in-line, and it worked again. This led me to believe that the new indicators themselves were the problem.

    To test the units themselves I connected them directly to a 9V battery. They both worked fine. I also tried them with the resistors in-line, and they still worked. This led me to believe that there was something about the power coming through the bike wires that wasn't agreeing with the LEDs (I was quite confused by this point!)

    After posting here and getting all the above replies, pretty much all of which mentioned the polarity dependent nature of LEDs (which I was previously unaware of) I thought that may be the problem. I had thought that I had tried swapping the wires over in the first place, but I wasn't sure - it was the early hours of the morning and I was cold and frustrated after no success!

    So tonight I decided to give it another shot. Armed with a quality multi-metre and some crimp connectors I decided to try the other side first, to see if anything was different. Typically, the unit lit up immediately. After some stuffing around securing the actual unit to the fairing (the wiring is the easy bit once you've got the connections sorted) I moved to the other (damaged indicator) side. I tried again with the wires connected logically (+ to + and - to -) and it didn't work. I switched the wires from the bike and the unit lit up fine.

    So the problem was indeed current flow in the wrong direction - at some point in my bikes history (I am at least the 3rd owner) the indicators were re-wired and one of them was reversed. The change must be somewhere at/near the relay, as the colours at the indicator are reversed. Since the stock incandescent indicators worked fine either way it was just left. This also explains why the alarm I fitted recently doesn't flash the indicator on that side when it arms/disarms - the send from the alarm is connected to what turns out to be the neg side.

    Anyhoo, I now have two nice little LED units on the front of my bike that are flashing correctly! The install is a little ghetto at the moment (stock plates on one side and a large washer on the inside to secure it - I'm waiting on some proper masking plates and rear flashers from RatedR, which should arrive this week.

    I'll post some more details of fitting and photos here: https://netrider.net.au/forums/viewtopic.php?t=63316&highlight=

    Thanks again for all the suggestions!
  13. bingo

    yeppers they are a diode they only let current pass one way. so you have to have them the right way around there is a cathode and an anode, and google is your friend too, not just NR
  14. Will they work without using the resistor :?:
  15. Possibly, but will usually flash faster and/or blow up after not too long.
  16. Read the post - indicators were supplied with resistors.

    Now I just need some for the rears, which weren't supplied with them, and reduce the load enough that the flashing is too fast.
  17. Yes all leds will work without a resistor but they will blink fast due to there lower current draw, the flasher relays are designed to work at a particular load current which adding leds makes them go to default fast blinking which is also warning you get on most bikes when you have a blown bulb. There are 2 ways to fix the fast blinking when you fit leds either replace the flasher relay unit to a led compatible unit or fit resistors inline to each lead which keeps same current draw as if using a bulb so flasher relay works as normal. The only draw back with the resistor option is the heat they generate so you need to have them well insulated or mounted away from your plastic fairings or anything they can melt.
  18. They won't ever blow up, only flash too fast :)
    The resistor goes in parallel with the indicator, not in series so it's not a protection resistor.

    The best thing to is to replace the indicator relay with an electronic one. These cost $45+ from many bike shops, but get them from here for only US$8.95!!:

    go to www dot superbrightleds dot com

    The most common flasher is LF1-S-FLAT, and this is a pin compatible with many modern bikes.

    These things are so chaep that I had to buy a batch of 5 and some other things just to get the minimum order :)

  19. OK, resurrection time - have put LEDs on the rear as well, these ones came without resistors.

    Went and bought a couple of 4.7Ohm ceramic resistors from Jaycar. Tried wiring tonight, and no effect whatsoever on the (now fast) flash rate.

    Jason, you're saying the resistor needs to be in parallel with the indicator? So in idiot speak bridging the + and - wires of the indicator unit? That's one thing I didn't try!
  20. Sorry, I missed this response, so you've probably fixed it already :)

    Yes, they must be in parallel, bridging the +ve and -ve.
    This sounds odd, as it's creating an 'almost-short-circuit' between the wires, but this is what a bulb does, as a 30W bulb only has a resistance of 4.8 Ohms (Resitance = (Voltage * Voltage) / Wattage)

    Most indicators are only 10W bulbs, so if you are fitting two lots of LED indicators (front and back) then the 'correct' loading is 7.2 Ohms, but a 4.8 should also be fine. If you only fit one pair (front or back) then you only require 14.4 Ohms, as the existing bulb will provide another 14.4 Ohms, and in parallel will give a total of 7.2 Ohms.

    The best thing to do is to replace the indicator relay completely with an electronic one that doesn't need any load. As I said earlier, at $8.95 from www.superbrightleds.com you can't go wrong, and they work with any combination of LED and incandescent bulbs.