I've had a broken WAH pedal on my shelf for years. Finally probed it and determined the foot switch is the problem. However I'm not sure if the foot switch itself is
AMT WH-1 - wah-wah for guitar - Optical WAH-WAH pedal for guitar
Jim Dunlop CONSEB004FFS0XU Dunlop 105Q Cry Baby Bass Wah Pedal featuring Wah Effects Optimized for Bass Frequencies and Auto Switch Off with Instrument and