Replaced the Control Module. A known problem with a bad solder connection on heater relay.
Removed door front panel containing control module, wiring, door latch, and ON/OFF switch. Unsnapped the holding brackets (mostly plastic) from the front cover, then the control module. Unplugged control module, then carefully worked it out of the metal framework. Reversed procedures to install a new control module. Was careful handling the front cover, as the "piano key" pushbutton switches and red "lights" would have all fallen out, all over the floor.