First not familiar with exact product , however troubleshooting is common. This is if pedal can be unplugged and you have access to volt meter (these are cheap enough under $20 and have other uses to support purchase) , set meter to measure continuity, set meter to lowest ohms to start. Before using on pedal touch the red and black leads together, touching the result should be zero on meter, not touching infinity or blank. Connect leads in various manners to the pins or sockets move pedal. If your meter reads a high number while moving pedal you have an open circuit. If you see the meter fluctuate as you depress pedal that would be expected ( normal) but then when fully depressed go high ( open) your pedal switch is faulty. The variation in resistance as you push pedal slowly is what varies the speed.
Answers & Comments
First not familiar with exact product , however troubleshooting is common.
This is if pedal can be unplugged and you have access to volt meter (these are cheap enough under $20 and have other uses to support purchase) , set meter to measure continuity, set meter to lowest ohms to start. Before using on pedal touch the red and black leads together, touching the result should be zero on meter, not touching infinity or blank. Connect leads in various manners to the pins or sockets move pedal. If your meter reads a high number while moving pedal you have an open circuit.
If you see the meter fluctuate as you depress pedal that would be expected ( normal) but then when fully depressed go high ( open) your pedal switch is faulty. The variation in resistance as you push pedal slowly is what varies the speed.