For 2003-2006 build date R1150R:
Headlight low/dip-beam powered through fuse 8, then through headlight relay as mentioned above. This relay is NC and switches off power to low beam filament when the high beam (fuse 9) circuit is energized.
So confirm status of fuse 8, then check the relay.
You can check continuity of the low beam circuit by pulling fuse 8 and the headlight bulb, measuring resistance from fuse pin 56b to bulb connector pin 56b (convenient notation).
As for those LED signal mirrors:
Years ago I talked with the Kisan folks about the circuit characteristics of the auxiliary jacks found in the top of the SignalMinder SM-5 module used for vectraLights add-ons. Cannot find my notes file, but IIRC there's 12v, ground, and a logic or PWM line for each side, left & right. The jack is a modular phone handset cord connection (see reference
http://en.wikipedia.org/wiki/4P4C#4P4C). I bought some R9 plugs, handset straight cord, and the required hand crimper tool in order to add some LEDs that would blink with turn signals and illuminate when the SM-5's Running lights feature is used.
You might take advantage of your SM-5's capabilities by using the add-on jacks to power your new LED mirrors, thus avoiding any OE wiring hacks. If interested in doing so, I can dig up the Kisan info (or call them again) and make up a couple of connector wires for you. Technically speaking, the wire length required to span fuse box to handlebar mirror mounts will be mega-long-a$$. You pay shipping!