pug 106

Do you have a multimeter? If so (and they're only £5 from Maplin) then you can check whether you have 12V on the connector to the bulbs. You can also check earth continuity back to the battery negative. Presumably you have both main beams out? If so it's likely to be either the switch in the steering column or a relay. Just checked the Haynes BoL and it says Bulb blown, corroded contacts on bulb or holder, fuse, relay, broken, loose or disconnected wiring or faulty switch.