do you mean that you have a switch with two grey wires one one terminal?and a black wire on the other?you are not very precise to let you understand,there are no neutrals on a light switch,all are live,never mind the colour of the wires,light circuits are very simple,
without seeing them,its hard to give you advice two way switching has a wire going to l1 to l1,l2 to l2 and common to common these are normanly yellow and blue,and red to common .
gts
September 2010