OK, problem solved. No rodents, no troubleshooting, and no head scratching!
I opened up the side panel from inside the coach where there is a rats nest of wires. Just what I expected. The bundle of wires that were grouped together for the three cruise control switches were ty-wrapped. Also, seemed logical.
They were very tight because of the way they ty-wrapped. After cutting it to access the individual wires, the problem became obvious. The middle switch connector, "Cruise Cancel", had been pulled completely off the switch. I suspect this was because of the weight or tightness of the bundle.
Anyway, plugged it back in and everything worked as it should.
It goes to show you that sometimes the solution is just so simple, you are caught off guard.
Thanks to all who took the time to guide and advise me, and help me fix this problem.