Replace the LED, maybe?
Imagination is more important than knowledge...
It is a miracle that curiosity survives formal education.
- Albert Einstein -
Quote by Bertallica
Replace the LED, maybe?

This, or broken connection. Buy another LED and with the pedal on place the wire ends at the same points as the current LED. If it lights up then the connection is good and the problem is the LED. If it doesn't light up there is a problem in the circuit.