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LED Turn Signal Problems (again)

Discussion in 'The Garage' started by xsdoug, Jun 13, 2011.

  1. xsdoug

    xsdoug XS400 New Member

    I've seen a ton of posts on this in the forums, but maybe I'm missing something here. I have a 1981 XS400. When I hit the turn signal, all 4 signal lights blink, at the correct speed. They are all LEDs.

    I bought the recommended Tridon EP34 flasher which is supposedly LED compatible, installed it, and it does not light up the lights at all when I hit the turn signal switch. It plugged in to the factory harness just fine and the pins appear to be the correct ones.

    I measured the output of the original flasher, it bounces between 12 (nominal) volts and 0 when flashing (as expected). I measured the output of the Tridon flasher. It sits at 6 volts steady, which is not enough to light the lights. When I hook a (incandescent) test light up to the flasher output as well as leaving it in circuit and touch the probe to the battery, the flasher starts flashing like it should, and also starts flashing the LEDs at the same time. Output voltage is 12 and 0 volts.

    So, I obviously have some sort of resistance problem going on here and the test light triggers the flasher to work, but I thought the Tridon flasher should have taken care of all that. Something else to note is that original flasher says "For LED" on it, but there's no other part number or brand on it, so I'm not sure where it came from. It seems like both of these flashers should work without concern of the bulb resistance, but neither does properly.

    I am considering just going back to stock incandescent signal lights, but it would be nice if the LEDs would work without resorting to resistors.

    Can anyone offer some guidance?

  2. frwinks

    frwinks XS400 Addict

    I've been trying to get mine working as well..My rear signals only have 6 leds per side, even with the tridon flasher still not enough draw:banghead: I just bought some small halogen signals for the front to make it all work..
  3. xsdoug

    xsdoug XS400 New Member

    From where did you buy them? I'm looking for OEM-style replacement lights, but I'm not really familiar with where folks go to get parts for these bikes. I found mikesxs, but most of that isn't for the 400.
  4. frwinks

    frwinks XS400 Addict

  5. jmd_forest

    jmd_forest Bldg 1980 XS400 Cafe Bike

    I'm having a similar problem as XSDoug. I replaced the turn signals with LEDs and all 4 signals light up when I flip the turn signal switch. Although I currently have no flashing I have a "zero draw" universal LED flasher on order that I am expecting to remedy that problem.

    Getting back to the problem with all 4 turn signals lighting up ...... I traced through the wiring diagram and discovered that 12V feed from the right signals and the 12V feed from the left signals are connected to either side of the turn signal indicator lamp in the instrument panel. What seems to be happening is that anytime the switch is turned on, the 12V from whatever side is selected is also fed to the instrument panel light, runs thru the instrument panel light and into the 12V feed circuit of the opposite side. This energizes the opposite side and lights up the LEDs of the opposite side. I confirmed this by unplugging the instrument panel lights and than only the selected side lights up. I don't see why this doesn't happen even with standard bulbs?

    Has anyone remedied this situation other than using load resisters? I was thinking of inserting a diode into each of the 12V feeds going to the instrument panel turn signal indicator light, tieing the lines together feeding only one side of the bulb with the 2 lines and actually grounding the bulb on the other side??
  6. bcware

    bcware Well-read Top Contributor

    I have used load resistors, but they result in a messy wiring harness and produce a small amount of heat. I got them from radioshack in the store.

    xsdoug, from what I remember the terminals on the flasher harness needed to have their positions swapped for an ep34/36 to work. Also, the original person to use an ep34 posted photos and I swear they were of an ep36...
  7. jordan

    jordan 1980 XS400H

    use hand signals
  8. jmd_forest

    jmd_forest Bldg 1980 XS400 Cafe Bike

    Thanks jordan, I waved my hands a few times and now the blinkers are working perfectly.

    It looks like I may be fiddling with this a while to sort things out. If/When I come up with a solution I'll post it in a new thread. Meanwhile, if anyone has solved these 2 issues without resistors please post a response.
  9. bcware

    bcware Well-read Top Contributor

    Unless your harness was modified the only success stories I have heard without using resistors involved an aftermarket flasher with the leads rotated on the harness to match the flasher since none of them are the correct orientation out of the box.

    Consider taking the headlight off and looking at the harness; many of the connections are behind it. Everything is color-coded.
  10. jmd_forest

    jmd_forest Bldg 1980 XS400 Cafe Bike

    I have a universal motorcycle zero draw flasher on order from superbrites that I expect to take care of the flashing issue (fingers crossed .... the "electronic LED flasher" I bought at the local big box auto store did not work). I have the headlight apart and access to all the internal connections which is how I was able to disconnect the instrument panel lights to verify side to side feedback through the tun signal indicator bulb as I suspected from tracing through the wiring diagram.

    I'm puzzled as to why the standard turn signal bulbs on the opposite side don't also light up whenever the turn signal switch is activated, considering the factory wiring has the indicator bulb grounding through those bulbs. It must be the voltage drop and current draw of the indicator bulb doesn't leave enough voltage/current to light the opposite side lights.
  11. robindean

    robindean XS400 Addict

    I'm attempting to get my LED signals to flash properly as well, only my biggest issue is GETTING TO the stock flasher. It seems to be completely enclosed/attached somehow between the mounts of my Seca's suspended engine. Oy.

    Is there a secret to this that I'm missing?
  12. bcware

    bcware Well-read Top Contributor

    I'm not sure about a Seca, but on my '78 the flasher sits in a rubber "barrel" attached to the battery box. It took some effort to pull it free.
  13. mogie

    mogie XS400 Enthusiast

    look for my post in the "another dreaded led turn signal thread" thread. I am using that flasher with no resistors and all signals work fine. You just have to wire one of the flasher terminals to ground. Real simple and cheap. I have pictures there of what i did. hope this helps.
  14. mogie

    mogie XS400 Enthusiast

    oh yeah, they do not auto cancel just so you know.
  15. jmd_forest

    jmd_forest Bldg 1980 XS400 Cafe Bike

    I suspect that the flasher you are using with the ground includes a built in resistor wired parallel to the LEDs. Does your indicator bulb work correctly?
  16. jayel

    jayel #9 Guru 78 SR500 80 XS11

    the problem may be the way Yamaha wired the turn signals to use a single bulb as the indicator lamp, using incandesent bulbs the voltage/current draw is enough that the non-lit side is "seen" as ground
    Last edited: Mar 3, 2012
  17. jmd_forest

    jmd_forest Bldg 1980 XS400 Cafe Bike

    I like your solution of running the indicator bulb directly off the flasher power going to the turn signal switch. Very clever. However, that requires splicing into the power line, probably near the turn signal switch and running a new wire into the headlight assembly. I'm thinking of mods totally internal to the headlight wiring by adding a diode to each side feeding the indicator bulb and then tieing those 2 lines together to feed one side of the bulb and grounding the other side of the bulb. I'm going to have to look into threading a wire from the switch to the headlight thru the existing wire loom to see if your solution can be done with a factory look.
  18. jayel

    jayel #9 Guru 78 SR500 80 XS11

    Brown/White wire inside the headlight shell or where ever the handlebar switch wire ties into main loom
  19. robindean

    robindean XS400 Addict

    If you do this, I'd very much like to read the result.

    Keep this in mind, as I believe it does contribute ... when I removed only ONE bulb from one side of the signal (rear, left) and replaced it with an LED, the single incandescent which remained up front did NOT draw enough power to cause flashing by itself.

    I wouldn't assume that there's a resister in the s-41-flat flasher I bought. I would more expect that it begins flashing as a result of electricity being present within it's circuitry.
  20. XSLeo

    XSLeo XS400 Junkie

    Your indictor light or lights have to hook after the turn switch. If before, it may flash the indicator all the time with out the turns flashing. Or just light up. That might be ok it just might be lit all the time, then flash when the turns are used, just have to try it.
    I doubt it will flash with just the one small bulb unless you use a flasher that isn't load dependent. As in the LF1-S-Flat I reccomend. That will flash just one bulb.
    If your turn signals are mounted as the stock signals are, hooking into the wires in the head light is the easiest place to tap in for the indicater light or lights.
    Use two diodes hooked from each side then together and to the positive side of one bulb, LED or regular.
    I may try that. Right now I'm using the amber indicater on the dash as one side, the white indicater as the other. A nice bright amber LED in place of the bulb in the amber light with the diodes will work well.
    I have all the wires ran to the dash, Just need the LED, I have diodes.
    I'll just have to do that.

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