Thanks heaps for posting this info, i think you may have just helped me with a problem i had been having with my KISS pin  

What I have found is that the ''crap'' that builds up on the switches over the years will combine with moisture to form a bridge strong enough to trigger a switch, particularly if it has a cap on it.  When my machines were in an uninsulated shed, and cold, damp winter air occured for a few days, some of my Ballys were unplayable!

I had this issue (still have it after a lot of rain) with my KISS, where if you started a game the right bumper would go completely ape shit, firing continuously! I too spent hours trying to track this down, even swapping boards etc all to no avail   In the end i found if i unplugged the switch matrix connector going to the CABINET switches, the game could be played (removed the connector after starting a game).  

The last time the game started acting up in this way, i got my heat gun and blew hot air into the cab while it was doing the bumper firing on its own thing.. it stopped within about ten seconds and functioned normally!! Ever since the if i wanted to play KISS and we'd had a lot of rain i'd just blow hot air into the cab   But now, armed with this info i think i'll be changing a few switches  

Btw, this NEVER happened on any of my other Bally or Stern games. They are all in the shed which i insulated as much as i could do when i moved in to the place.

Thanks again