Have you checked that the switch in the faucet is good? You can do this by disconnecting the wires to the faucet, and connecting an ohm meter to the wires. You should see open circuit when the faucet is off, and a short (nearly 0.0 ohms) when it's on. You'll probably see something like 0.2 ohms or so, depending on your meter and the resistance of the test leads.
