I looked at some of the (USA)People wiring schematics, although I havn't seen one for the 150-it looks like most of the lighting circuits are about the same. The hot wires at the head light socket are (l) and (w)and green (ground) After a short distance there is a connector, the wires now get a stripe-and turn into the L/B wire and the W/B wire . These are tied into the pass switch(to make both beams low and high to come on), so the pass switch and obviously the ground circuits are OK. The light switch or the light control (relay) it will have 6 wires green,r/y,l/b,w/s,l,w/h. the plug or a terminal may be loose. look at the wires from your headlight, follow them to the connector where they change from a solid color wire to a solid color with a stripe. note these colors-they stay the same colors as they go to the light switch and the relay. I suspect the relay is inside the front fairing/body work. Look with a small flashlight through the side radiator vents if you spot it.Hope this helps
