kenmore elite electronics

our dishwasher will not start. when we close the door, all of the buttons seem to function (lights come on), except the start button. i have disassembled the little bit of the electronics there is, and see nothing obvious wrong. i tried jumping the door lock switch, to see if that did anything, but it did not. i think the start button may not be working. but i can not find an electrical schematic so i can try to test it. i do not want to start jumping wires on the board, for fear of really messing things up. a new switch assembly is $90.00. which is not cheap enough for me to order, and set aside if that is not the problem. since there is never any returns on electrical products, i do not want to guess time after time until i stumble across whatever is wrong. can anyone point me in a direction for a schematic? or a real trouble shooting guide? i am a retired (involuntarily) repair tech, so i have some diagnostic skills. but not from this field. and trying to work blind is never easy. thanks.