Sorry, I'm of no help, but, man, what a terrible turn of events.
Having been on (too many) forums for these trucks, cannot say I've heard of that issue until now. Best of luck getting it repaired!
But, are you saying that whole switch bank was intermittent or not operable at all prior to the first replacement of the switch bank and then it worked 100% of the time for a couple months and is now intermittent again?
If so, that seems to me to be either the new switch bank or possibly a bad connection. If the new switch fixed the same condition previously.
