No spark from the coyle

I have a 1986 silver spirit rolls royce, it broke down driving along the road, since then it will not start, I changed the little coyle in the distributor, changed the ignition module (black box on the right hand side under bonnet) removed coyle and fitted it to another car and it works. Power to the positive on the coyle is ok, negative on coyle to earth will light a bulb, where does negative on coyle go through to reach to power distributor. Can anybody help with this