i have a sp3420 that will work fine for weeks then wrench light comes on and cuts everything off then for a few day it will continue teven after a few key cycles. no codes at all i have service tool and all limit switches are working i've tested all over the mast cables for continuity even with platform raised slighty and me jumpiing up and down to see if i lost continuity. all wires tested good. no flash codes on any of the access modules please help.