auxiliary lighting wiring

I'm new to the forum, though I've been lurking for a month or so since I picked up a 2007 GRiSO 1100. The bike needs some extra lighting up front for visibility, if nothing else and I thought I'd wire it to the headlight. I noticed there are 4 wires going to the headlight harness, blue, black, white and yellow. Does anyone know which is live and which is the ground? Or is there a better place to wire in auxiliary lights? Thanks.

Welcome !
Congrats on the GRiSO - I have a 1100 also.
You'll find a link to Carl Allison's excellent wiring diagrams in the 'Ex Libris' section of this website, under the 'online manuals' tread.
(Blue is the ground).
However, if you're adding significant current draw (ie large lights) I would run a separate fused, feed from the battery. Otherwise, you'll increase the load on the existing wires and (more importantly) the switch contacts in the bars.

Good luck, and remember the Harley Mantra: "If you can't fix it with a hammer, it's an electrical problem".

I bought my LED headlights at :

[You must be registered and logged in to see this link.] LED light Model 44, (they also have a brighter one Model 60) together with the brackets and a rotary switch.

I have connected the rotary switch to an electric harness I bought at [You must be registered and logged in to see this link.]

This guy (A Canadian guy in Japan !!!) builds quality stuff, the connector has three circuits two switched (with a relay) and one unswitched. I use the switched circuits to connect the LED lights as well as the heated jacket. The unswitched is so far unused. Here is the link

[You must be registered and logged in to see this link.]

The LED lights come on when the ignition is on and I can then adjust the intensity with the rotary switch. In practice the LED lights are always on when I ride and I don't bugger about with the intensity, I figure that high is good enough and give me plenty of visibility to incoming traffic. The rotary switch has an extra lead that can be connected to high-beam, but I didn't bother, as I said I like the high intensity setting.
here:

Hope this helps