Tail light gray ground wire help
  • taylormahoney25
    Posts: 3
    Joined: Sun Feb 21, 2021 6:46 pm

    Tail light gray ground wire help

    by taylormahoney25 » Sun Feb 21, 2021 7:01 pm

    Having issues with the tail light on my '05 450x. Installed another DRC light a few months after breaking my last one. It is wired correctly, but seems to not be getting a ground on the gray wire coming from the ECU. If I touch the tail light black wire to a ground with the bike running the light comes on, and my multi meter seems to confirm that the gray wire isn't giving the ground it should. I guess whatever electrical switch is inside the ECU is dead.

    Looking into it further, it seems that if this is bad, there is nothing to do except replace the ECU, or maybe install a switch to a ground wire and run the light off that, or someone somewhere said they ran it off their headlight...

    I don't really want to have a switch that I must remember to turn on and off, but how would I connect it to the headlight ground? What are the possible pitfalls of this? Does anyone have any other ideas or workarounds? Something I missed or may not be thinking of?
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    JimDirt
    Posts: 4406
    Joined: Sat Nov 25, 2006 6:31 pm

    Re: Tail light gray ground wire help

    by JimDirt » Mon Feb 22, 2021 12:33 pm

    Welcome to the site !! \:D/

    OK , I just checked my 06 with a test probe and it seems the Black wire is Hot as long as the battery is hooked up , so constant power to it , the ground seems to be controlled by the ECU , so , with that said , What you are going to have to do is find another source that Grounds when the bike is running and not grounded when it is off .... The headlight is not that source as I just checked mine and there is no constant power to the headlight , meaning it has a constant ground , and if you tapped into it you would have the light on all the time

    The other way around this (without replacing the ECU) is to change the connection TO the taillight and make it a power wire that only is on when the bike is running , and just put a loop connector to the gray wire and ground it to the battery or engine and make it a constant ground .... those are really the only options I see that would eliminate replacing the ECU or putting a physical switch on the ground wire ...... :-k 8-[

    I am assuming you have a Manual/Wiring Diagram , so just check power connections at each source and see if any of the others have constant power , which would hopefully mean that the ground is generated when the bike is running ... otherwise you would need to change the connection locations like I suggested .... or go on EBay and find a used ECU for a lesser cost .....
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  • Back2-2
    Posts: 1148
    Joined: Tue Jan 04, 2011 3:31 pm

    Re: Tail light gray ground wire help

    by Back2-2 » Mon Feb 22, 2021 12:55 pm

    Just jumping in on the tail of Jim's comments. The clutch safety switch might provide what you want.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
  • taylormahoney25
    Posts: 3
    Joined: Sun Feb 21, 2021 6:46 pm

    Re: Tail light gray ground wire help

    by taylormahoney25 » Mon Feb 22, 2021 7:03 pm

    Welcome to the site !! \:D/

    OK , I just checked my 06 with a test probe and it seems the Black wire is Hot as long as the battery is hooked up , so constant power to it , the ground seems to be controlled by the ECU , so , with that said , What you are going to have to do is find another source that Grounds when the bike is running and not grounded when it is off .... The headlight is not that source as I just checked mine and there is no constant power to the headlight , meaning it has a constant ground , and if you tapped into it you would have the light on all the time

    The other way around this (without replacing the ECU) is to change the connection TO the taillight and make it a power wire that only is on when the bike is running , and just put a loop connector to the gray wire and ground it to the battery or engine and make it a constant ground .... those are really the only options I see that would eliminate replacing the ECU or putting a physical switch on the ground wire ...... :-k 8-[

    I am assuming you have a Manual/Wiring Diagram , so just check power connections at each source and see if any of the others have constant power , which would hopefully mean that the ground is generated when the bike is running ... otherwise you would need to change the connection locations like I suggested .... or go on EBay and find a used ECU for a lesser cost .....
    Thanks for the reply! Those are some good ideas, and yes, I do have a decent manual for the bike. I will get busy with the multimeter this week when I have some time.

    I like the idea of finding a power that’s only on with the bike running, but will see what makes sense
  • taylormahoney25
    Posts: 3
    Joined: Sun Feb 21, 2021 6:46 pm

    Re: Tail light gray ground wire help

    by taylormahoney25 » Mon Feb 22, 2021 7:04 pm

    Just jumping in on the tail of Jim's comments. The clutch safety switch might provide what you want.
    I good idea. Will look at this possibility with the multimeter later this well hopefully

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