I am afraid that things get a little murky for me to remember from here on in. What I can tell you is, the Buell headlight bulbs are different then the Suzuki bulbs. Also, the Strom headlight bulbs both illuminate on the "Low" setting, and they both illuminate on the "High" setting. The Buell headlights work with only one bulb illuminating on the "Low" setting, and both bulbs illuminating on the "high" setting.
I had rewiring to do to make this all work!
Here is the Buell headlight harness plug.
There are only two wires "feeding" each bulb on the Buell setup.
Here is the OEM harness plug. The photo also shows three wires feeding the Strom headlights.
So, of course, the first thing I had to do was cut the Buell plug off of its harness, so that I could to begin to identify what wire did what.
I also had to open up the light switch housing on the left handlebar grip.
Using the Buell headlight assembly, laid out on top of a cardboard box, sitting right next my bike, and the stock switch and wiring from the bike, I was able to determine, "what wire did what", when I flipped from "Low Beam" to "High Beam".
With that information, I began cutting and soldering the stock wires into the positions that I needed them to be in to make the Buell headlights work. (Believe me, I haven't a clue as to what I am doing here!!! I can't remember what I did!!!)
It was easy enough to identify which were the ground wires on the Buell lights. I soldered them together.
Here is "Low Beam".
And, here is "High Beam".
However, the above setup is wrong. I didn't discover it until I rode the bike at night. The "Low Beam" light on the Buell assembly is the RIGHT headlight and bulb. "High Beam" is the LEFT headlight and bulb + the right headlight. There IS a difference.
Since doing the above work over a year ago, I made some wiring adjustments when I built my front fairing.
Now, that was a lot of fun!!!!!