Repairman,
Those switches according to the manual are those finger type switches with the clear plastic cover mounted on the connecting bars between the lever assy and the control valve correct?

Why did cleaning them help? Like i said earlier it could have been trash or carboned up contacts and spraying them down cleaned the contacts enough to make them start working again. Or it could have been co-incidence and you moved a bad connection in the harness inadvertantly allowing it to start working again. One of the switches may have had a stuck contact and you freed it up.

There can be many reasons that caused this so nobody can definitively give you a full proof answer. But due to the nature of how these switches work i'm bank on one of the contacts being stuck and when you activated the circuit it caused it to error. But that's just an educated guess having dealt with these before.

I would order a couple and keep them on-hand just in case this happens again, then replace the bad one once you find it.