Author Topic: new LED speedo / Neutral light not working  (Read 251 times)

Offline cafeGS

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new LED speedo / Neutral light not working
« on: January 11, 2018, 02:50:11 AM »
Hello all!

I've got a 2006 GS500 and I've swapped out the tach/speedo for a smaller styled one (as linked below)

- I can't get the neutral light to work with the new LED.... the high beam, indicators and backlight are working as they should. any suggestions?
I've tried adding the old bulb along the line to the led to see if it needs that exact draw amount but it'll only light up the bulb.. not the LED :/

Thanks for your time guys and girls

https://www.ebay.com.au/itm/Universal-Motorcycle-Dual-Odometer-Speedometer-Speed-Gauge-LED-Backlight/202100592613?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Offline TGTwin

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Re: new LED speedo / Neutral light not working
« Reply #1 on: January 11, 2018, 09:18:56 PM »
I'd try putting direct 12v across the neutral LED wires just to confirm it's not a dead LED.
If it lights the old neutral bulb when they are all in series, then I'd say either a dead LED or the wiring is wrong somewhere (either + and - switched, or a loose connection maybe in the speedo itself).

Slightly off topic, have you gone for a ride with this speedo yet? Is the speed accurate? I've always looked at these cheapo ebay speedometers but could never find what size wheel they are for and so how accurate the speed would be.

Online mr72

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Re: new LED speedo / Neutral light not working
« Reply #2 on: January 11, 2018, 09:53:03 PM »
You know the LED is not backwards or hooked up with backward polarity because if it was then it would not work with the original bulb in series. LEDs don't conduct when reverse-biased... they are diodes after all.

However if the LED doesn't light and the bulb lights when connected in series with what should be the LED, then the LED is conducting. Or the speedo unit is conducting in lieu of the LED. If it was me I'd use a multimeter with diode function to test the LEDs as diodes. Of course if it were me I'd crack open the speedo and trace the wiring and ensure it's actually wired correctly. An ohmmeter would tell you quickly if the LED leads are shorted.

I agree that you should test the LEDs by themselves and ensure that the wiring is correct and that when hotwired the LEDs will light. I would not test this with the motorcycle battery though, I'd first test with an ohmmeter to make dang sure they are not shorted. Connecting the MC batt to a shorted LED would be a big mistake.

It is possible for LEDs to go bad I guess. Surprising they'd fail short. If those pins are shorted then it's a build failure that you might be able to correct with some soldering, or with a return label.

Offline cafeGS

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Re: new LED speedo / Neutral light not working
« Reply #3 on: January 12, 2018, 12:17:10 AM »
Thanks guys I'll try testing with my multimeter tonight.

I've also contacted the supplier and they said they'll get back to me... (won't hold my breath)

but yeah it was just a cheap speedo on Ebay... the speedometer is reading correctly... I had another one and it was a long way exaggerated from the bikes real speed... it would surpass 180k/m when I'd overtake a vehicle!

Cheers, Sam

Offline Big Rich

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Re: new LED speedo / Neutral light not working
« Reply #4 on: January 12, 2018, 01:21:12 AM »
Just making sure - the new speedo's neutral light is wired to a ground signal, right? The high beam , turn signal,  etc are all positive signals (so when your high beam is on, a positive wire is what lights up the blue led).

Assuming it is wired to the OEM ground signal, check the ground wire from the battery (to the harness and the frame).
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Offline gregjet

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Re: new LED speedo / Neutral light not working
« Reply #5 on: January 12, 2018, 07:30:02 PM »
Yeah most likely covered above. Dead led, LED has been put in the wrong polarity or you have a grounding problem to the LED.
So long as it isn't an SMD board the led is on you should be able to fix it for next to nothing if they don't replace it ( they should if it's faulty). Even if it is an SMD board you can often cut the led and use the internals as tag posts to put a new one on ) been there done that).

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Re: new LED speedo / Neutral light not working
« Reply #6 on: January 12, 2018, 07:54:47 PM »
if an ordinary bulb lights when put in series with the LED, then the LED cannot be backward (no current would flow) and the LED can't be failing ground (no current would flow). It has to be shorted.

Offline cafeGS

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Re: new LED speedo / Neutral light not working
« Reply #7 on: January 18, 2018, 01:24:33 AM »
So an update... who would have thought a cheap speedo from eBay could be so... well... cheap! Theres no point in trying to get the neutral light to work seeing as the speed isn't correct AND the trip meter/odometer aren't really doing their thing either. I've not had any problems putting one of them onto a few Hondas in the past. But anyway I'm now going to attempt a digital speedo with a magnet pickup on the rim... wish me luck!

- thanks for your input everyone... I'll let you know how I get on.

Offline gregjet

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Re: new LED speedo / Neutral light not working
« Reply #8 on: January 25, 2018, 08:01:35 PM »
I put the magnet in the disc brake. You can buy speedo magnets from places that sell digital speedos that screw in the disc brake bolts.

Offline gregjet

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Re: new LED speedo / Neutral light not working
« Reply #9 on: January 25, 2018, 08:05:47 PM »
Note re the above. I have posted about using led flasher indicators before being problematic, because of the wierd wiring architecture that Suzy uses, so you may want to trawl for that if you are going to use them.