My headlights work fine, but when I push the switch to click it into High beam, the lights "switch over" but don't actually get any brighter, they stay the same as regular beam. However, when I pull the stalk forwards, Flash to pass, the beams get brighter as you would expect. In both instances, the dash light indicator comes on. What should I check for? The bulbs are brand new. Am I right in thinking it could be the multi function switch rather than fuses/relays?