With the side lights on only...no head lamps will be on....But as soon as you turn ignition on.....the the "Dim-dip system comes on...ie not on full power. you say the head lamps are coming on with out the ignition being on....ie working from just turning side lights on....yes...so there is a problem, i can tell you the system is complicated, it runs both head lamps in series....4 filements [ 2 in each head lamp ] are on...so low voltage now, hence there "Dim ".....back in the day best to convert the system back to normal head lamps ....Dim -dip not now required for MOT...i can tell you converting the system results in much better Head lamps . Peter