Thanks for the help in dirt....checked the 12v+/- on backplane and definitely not getting voltage there...5vdc ok...compared voltage on another car in the group with same readings,yet no problems with that car... yesterday I changed 12v battery in bottom of controller...awhile later ims started seeing car#2 intermittent ly then loses comm...it says no comm when I can get to the screen..weird...so...if I turn car on,cop car calls all latch,cop fire Svc light comes on,hall up/down directionals on at every floor,and all up/down calls for group latch at all floors sending other 3cars chasing them...when all calls are answered, things return to normal except the hall directionals stay lit....Oh and car won't run in any mode...inspect,normal,etc....