Author Topic: Speedo Wiring Help Needed!  (Read 268 times)

Offline brucedavidculver

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Speedo Wiring Help Needed!
« on: January 10, 2020, 08:48:33 PM »
So I am officially raising the white flag when it comes to wiring the new Dime City Cycles speedometer lights.  The funny thing is I just put one of these speedos on my GS 450 last year and had a similar issue, but that was easily solved... this has me stumped. 

Using the DCC wiring diagram I've wired up the new speedo and...

The neutral indicator works correctly (check)   
The oil pressure indicator works correctly (check)
The high beam indicator works correctly (check)

But... the turn signal indicator works as follows:

Put on the left blinker and the indicator flashes (correctly) / put on the right blinker and the indicator does nothing

-OR-

Reverse the two wires that run from the bike to the speedo and...

Put on the right blinker and the indicator flashes (correctly) / put on the left blinker and the indicator does nothing

So.... I know that this has to do with the fact that I am going from incandescent to LED lighting.  I've only got two wires coming from the harness on the bike and two wires on the speedo.  It would seem that the polarity of the wires from the bike are changing based on which side is flashing (and LEDs only light when the polarity is correct) which is why it's a "only one or the other works" situation.

The GS 450 had separate left and right indicator lights so I just had to splice the wires together along with Zener diodes (to keep the current running in one direction so it couldn't back feed to the other side and give me the hazard light effect) and that was it.  However,  since I only have two wires from the harness I don't have that option... and I can't seem to trace the wires back to where they must already be spliced to "unsplice" them (or whatever I need to do).

Any thoughts from anyone that has more electrical experience than me?  Which seems at this point to be anyone that walks upright and has opposable thumbs...lol

Help!

p.s. My "workaround' idea for this is to simply run a parallel set of wires from each front blinker (which will give me an independent + and - from each side) and then splice them together with diodes like I did for the 450...  then just cap off the existing wires from the harness and be done with them.  Thoughts on this? 

And of course... please call me out o wen any misinformation above.  If any of my assumptions are incorrect I'd rather somebody let me know so I can learn and not drive myself crazy.   :hithead:



« Last Edit: January 11, 2020, 12:58:49 AM by brucedavidculver »
2006 GS500F (latest project and probable "scrambler-type-thing")
2005 GS500F (“café-ish"mod)
2017 Benelli TNT600 SOLD
2004 GS500F (scrambler mod) SOLD
2009 GS500F (street fighter mod) SOLD
1982 GS450 (café racer mod) SOLD

Offline brucedavidculver

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Re: Speedo Wiring Help Needed!
« Reply #1 on: January 16, 2020, 01:29:21 AM »
Just a quick post in the hope that anyone else that has this same issue can use this as a resource. I never did figure out what the problem was with the original backlight wiring (might be an issue specific to my bike?).

In any case... I ended up fixing the backlight wiring issue by running the backlight LED in the new speedo off of the black and brown pair of wires that originally ran the small bulb under the main headlight (called the parking light maybe?).  Since the new dual headlight didn't have a secondary parking light, that wiring would have gone unused anyway.  Problem solved. The OE backlight wiring is now just tucked away under the tank.   

For the blinkers I did exactly what I had planned... ran a parallel set of wires from each of the front blinkers, added Zener diodes to the positive side of each circuit and ran them directly into the new speedo blinker LED.

Best of luck if you encounter the same challenge! 

     
2006 GS500F (latest project and probable "scrambler-type-thing")
2005 GS500F (“café-ish"mod)
2017 Benelli TNT600 SOLD
2004 GS500F (scrambler mod) SOLD
2009 GS500F (street fighter mod) SOLD
1982 GS450 (café racer mod) SOLD

Offline ShowBizWolf

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Re: Speedo Wiring Help Needed!
« Reply #2 on: January 16, 2020, 02:04:40 AM »
I am really glad you got something figured out!  :woohoo:

I'm familiar with that black and brown pair of wires, I used them to run the H7 bulb in the projector spot when I swapped my headlight for a gsxr one.
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