Nuvi to Tom Tom power supply ?

 

I have a Garmin Nuvi 295w. I want to splice in, connect to the supplied Tom Tom wire (hardwired from factory on motorcycle) that is outputting 5V with 2 wires 1blue, 1 green. The Nuvi mini usb has 1red,1black, 1 white. I have cut off the wire from a 12v nuvi 12v outlet (by passing the resistors since the Guzzi TT is only at 5v Safe for the Nuvi) and tried using the red and black connected to the green, blue from Tom Tom. not using the white. No go I checked with a v meter coming out of the 12v power outlet and the white wire seems to be outputting 5v +- The black nothing and the red? Any suggestions? The Nuvi might have something wired into the 3 wires that tells it to charge while navigating rather than just charge when hooked up to a PC usb. Any Suggestions? I'm not a wiring guru...

Since you already cut the

Since you already cut the adapter cord, crack open the cigarette lighter end, which you're not using, and see how the red wire is connected.

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Don't have a nuvi 295, but a different idea...

Why not wire in a 12V outlet to an ignition controlled source (running lights or such. I'm not familiar with guzzis) on the bike? Then plug the regular garmin adapter cord into it and leave the Tom Tom connection alone. Nothing much to figure out that way. I did this on my Honda Nighthawk (no factory anything on that bike) and it worked well with my nuvi 660. I now ride a Yamaha FJR which has a lighter socket inside a little glove box in the fairing. Got myself a 12V automotive usb adapter plug and a usb cord to power my 3490 cradle on the bike, works like a charm with a ram-mount to hold it securely.
Alternately maybe this thread will help with nuvi 2XX usb wiring:
http://www.poi-factory.com/node/10701
Probably not the answer you're looking for but maybe it'll be of some help.

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Garmin Nüvi 660 & 3490LMT with ecoRoute HD, Nüvi 855 gone to GPS heaven