The door switch was the culprit. When the drum light stays on all the time with the door closed and the unit will not start, I suspected the door switch was bad. The switch can be changed by not taking the dryer apart. I know that now. Took the top off, access the switch harness, unplug the cable, remove switch from front, test switch, ( a form C), replace switch with new, and reassemble. Problem solved. The electric schematic is in the panel below the door. Good to know!