Has anyone done this before?

Here's the story:
I thought my 77's driver broke, but it isn't, which leads me to the wiring, or could it be something else? I'm at a point trying to re-wire the eggo, but would like to consult before attempt.

A few questions I have:
- How to determine which part of the wire is malfunctioning?
- How to pull the wire out from the rubber sock around the head band and put it back in? Should I tear the rubber sock apart?
- Where to get the replacement wire? or could I re-use the existing wire?

Any advice is appreciated. Thanks people.