i,m trying to fit a new light but am having a problem, i have 3 red and black wires with earths but there is a single black wire on it,s own. have tried to connect with red and black in new fitting but nothing happened, have tried all red and black wires seperatley but havent used the single black one. i,ve checked my fuses and there ok so i havent blown a fuse by doing this. any help would be appreciated.