determine wires + or -

[bacongrease]

 So MG loves to have all negative wire to battery, unlike other bikes grounded to frame.  Battery is out.  I have 8 wires and I do not know the best way to determine if a wire goes to the pos battery post or the neg.  PO had various add ones, garmin, voltage reg...etc. so I dont know which are + or not.    . 

EDIT:  I determined the major + and ground..its all the other little wires ? ? Afraid to fry the ECU..

thank you                   

[Dr. Enzo Toma]

Not sure which model this is for, but for 8 wires I'd not run 4 to each battery terminal. Personally that's too much chaos for me. I'd add a power distribution module or a small fuse box. A bus bar if you want to go super simple.
What colors are used on the wires, if not red and black?

[moto]

So MG loves to have all negative wire to battery, unlike other bikes grounded to frame.  Battery is out.  I have 8 wires and I do not know the best way to determine if a wire goes to the pos battery post or the neg.  PO had various add ones, garmin, voltage reg...etc. so I dont know which are + or not.    . 

EDIT:  I determined the major + and ground..its all the other little wires ? ? Afraid to fry the ECU..

thank you                   

I might ttry each of them with a disconnected 12v battery after looking on their respective websites for information. If you're wrong, you won't hurt the ECU. Once you get it figured out I recommend the Fuzeblock FZ-1 or something similar to tame them all.

[aklawok]

USB outlet, grip heaters,sae powerlet, all going to the battery. Had the same problem on my CalVin a while back. Had to get longer battery bolts. Guzzi colored the main +/- wires but not the others, they are a little short where they come up to the battery too. Had a fit chasing my own tail when Missed connecting one of the grounds, it slipped behind the battery and caused a no start. I pull my battery for winter storage and have since put a zip tie on each set when I do, just to not mix them up again. A little black tape to flag the grounds works too.

[Dr. Enzo Toma]

I had a Fuzeblock FZ-1 on my V7 850 for a few years until it failed. I think it was water damaged, despite me having taped it up quite a bit when installed under the side panel on the bike. They're about $100, and I didn't need so many connections, so I replaced it with a Tusk accessory power harness good for 3 accessories at $45. It's worked just fine for powering 3 accessories. I have it powering my Garmin GPS and Koso heated grips with ignition on, and my GPS tracker all the time. For a switched-power trigger source, I have a posi-tap on the OEM accessory USB port installed under the seat of the bike.

Here is a photo of the Fuzeblock FZ-1 and Tusk accessory power harness side-by-side.





Here is a photo of the Tusk unit stuck to the battery holder on my V7 850.

[Dukedesmo]

Voltmeter/Multimeters are cheap enough and useful for many other applications.


Or, touch the wire to the frame - if it sparks it's positive.   

[guzzisteve]

Never did say what model or what color the wire were.

[wirespokes]

My 70s and 80s guzzis are grounded to the frame. I'm sure there are places on the frame to mount some of them. And on my bikes, the wires aren't long enough to reach where they shouldn't go. In your case, though, I'm trying to figure out how to tell which goes where and haven't come up with a solution. Touching a wire to the frame wouldn't work since the power isn't hooked up. Things like heated grips will work either way but the accessory and USB outlets need the correct polarity. I think there's only one way and that's to figure out where each wire goes and sort it out from there. Normally red is positive and black negative, but it sounds like that's not the case with you. Please let us know what bike this is and what colors the wires are.

[bacongrease]

   2004 Stone Touring.   I have it sorted.     All wires are black. 
   I haven't connected all accessory wires as the units are yet  not attached to the bike but I know now what the individual wires are for.  Thanks for all suggestions.
  My neighbor, the original owner hit a deer and went down.  With 4 rugrats to consider, and a wife, he sold the bike to me cheap.
  However, no gauges or tailights.  No problem,  but a slight  wiring challenge. 
It runs great, I like it a little more than my FXR.

[Dukedesmo]

Quote from: wirespokes on August 12, 2026, 10:38:49 PM

Touching a wire to the frame wouldn't work since the power isn't hooked up.

___________________ _________________

I was, of course being facetious about touching to frame as that won't do your battery (or frame paint) any good.

Really you should hold the frame with your hand and stick the wire on your tongue - shock = positive, no shock = negative. 

Seriously though, a multimeter is an essential tool for anyone working on bikes and you can, surely get a perfectly useable one for less than $20. 

[guzzisteve]

Glad you got it sorted. They usually STOCK had one big ground wire to batt & 2 wires to Batt positive, big black & small black, that's all.