I have a wall switch that controls ceiling light. It has 1 black wire and 1 white wire, plus ground. When I put a standard single pole dimmer switch in its place, I wired the 1 wall black wire to the 1 black dimmer switch wire and the 1 white wall wire to the other black dimmer switch wire. Then connected ground wires. Dimmer switch will now turn the ceiling light on and off, but it will not dim??? What is wrong?