I have a POD HD500X and the Wah has been working fine. All of a sudden, at a show, I step on the toe to engage and nothing...no Wah. The light doesn't switch for EXP. The VOLUME portion still works with the pedal, as in some of my presets have a volume and the pedal works for that...but turning on the Wah isn't working, and YES, I'm pressing hard enough.