The switch is on the backside of the pedal. The switch is a normally closed switch. Which means, when the pedal is at rest, no pressure, it will contact the switch and opening the contacts. The pedal is not returning all the way back. Check the return spring, make sure it is still there and not broken. If it is returning all the way back, push the pedal down and push the switch forward towards the pedal arm. Let the pedal return, it will push the switch back in the bracket, this is where it should stay. If it doesn't, replace the switch.