I'm still waiting for the answer to that one myself.
Guess I'm just going to have to find a set of schematics to do it the hard way.

 

I used those wires and spliced an iphone charger. Works like a charm

 

Would this connection work for a GPS unit? I bought a power cord for my GPS that connects directly to the battery. What I didn't think about ahead of time was... I can't leave it plugged into the back of the GPS when the bike is off without a drain on the battery. I guess it's constantly trying to recharge the battery in the GPS unit.

Am thinking this connector may be a better route to go because it won't be feeding power to the GPS while the bike is turned off correct?

 

Correct, you just have to add a fuse to it so that you wont burn anything important bro, mine charges fine when the bikes on as soon as i shut off the bike it stops charging

 

It's the Orange/White wire and traces back to the 15A accessories fuse (at least on HD's wiring diagram).

 

GREAT!....thanks.... would not want to use if it piggies off headlight.

 

My bike is an '03 Heritage Classic. Do I have this "spare" accessory plug under my seat? I want to add a cigarette-style plug on my handlebars. Does anyone have Harley Davidson Part #'s for all the stuff I require to plug-and-play?

 

And is this plug under the seat the diagnostic plug the dealer uses, or is that one under the gas tank? I obviously don't want to use that one for drawing 12volt power to a cigarette lighter.

 

Thanks for this instructional. It helped a ton!

 

Excellent work, thank you.
This is very helpful, especially since I need to power up a satnav.

Cheers