I suspect you guys are onto something.  While it works every time in switch edges AND I connected the wires together before the plug it still plays up. After I shorted these switch wires together it moved up about 1/4 of the way and stopped. Now it won't work again. In game play it says warning warning keep hands away - even with the switch showing closed in the switch edges matrix!

I guess I will look at switches up and down from it in the matrix?

I put new connectors on all the plugs at bottom of mpu as there was some corrosion.  But if this was an issue I would have thought it would take out a whole row or column - not just one switch?