@ Mcat: I am curious as to why you do not try to repair item number 4 shown on the diagram Tabora posted.
item appears to be a wire cable. It should be repairable unless the wire is broken off even with a molded plug.
I too have one of these ES6500's. I appreciate the post of the wiring diagram.
I opened the wiring harness area to install a frequency meter.
I can say that from what I saw the area is a rat's nest of wires and I am surprised you found the cable bad.
I captured the print with"wisdom soft screenhunter 6"
Some history on my ES6500: It was bought new in the 90's for $4800 by a deceased friend.
His widow call me and asked if I wanted to buy it.
I asked what her price was. She said $400.00.
The unit looks new as my friend took good care of it.
I installed a NG unit on it.
I still have it sitting in the corner of the garage.
My understanding is that the timing belts and the Voltage regulator are the main culprits for failure.
Good luck repairing your Honda.