My drivers side headlight has been intermittently working the last week or so...comes on and then goes off, always when car been stopped..normally a bit of twiddling sorts it..not today tho..just can't get it to work..not the bulb as I've tried it in the other side...can't see any loose wires but don't wanna mess too much as of high voltage...they are xenon bulbs so bloody expensive...any suggestions please???