Why won't my brand new wah pedal work?

I just bought a brand new Kirk Hammett signature wah pedal, and it's not working. I put in a new 9V battery, plugged a cable from the guitar to the pedal, and another from the pedal to the amp. I get a normal sound from the amp when the pedal is clicked on, but no wah effect. I have tried multiple batteries, as well as an adapter plugged into an electrical socket, but nothing seems to work. Am I missing something? Please help.