So, just an update... I replaced the wire in the knee pedal (quite easy) and also bought a new light instead of trying to fix only the crackled wire. I tested the machine and both the pedal and the light are working perfectly. Now the only thing left to change is the cord that leads the three pin terminal to the motor. I called a place here that does these services and the guy told me on the phone that it would cost about $ 10 to $ 15 for him to fix only the motor wire, but I still feel like I can do it myself, I'm still just trying to find out how.