I guess the light plug is not varible like the control. I have replaced cords & or plugs on controls. If the plug is pulled from the wall by the cord & not the plug, it can break wires. You can buy a new plug & cut off a short piece of the cord & rewire it. Sometime you can determine if this is the issue by flexing it while plugged in & you are pressing the control. If it kicks in & goes back off, that is the problem. You can buy generic controls for about $15-20 (for mechanical not electronic) & wire it in with your existing wires if you control has worn out. I'd say the higher % is the cord is broken at the plug.

Thanks Joan! First thing I did was check the plug and wiring. Did find the problem...a tiny coil wire under the contacts was broken. The new one should be here Wed.
Suzi

I fried my Singer 6235 foot pedal by having it on carpeting. The tech told me to not have it on carpet so I grabbed a cutting board and have been doing that ever since with all my machines. The sewing machine still lives and works well.

You can usually tell when a foot control is about to go because it will sew for 5-6 stitches and quit.