It is times like these, we all mutter, if only it could talk. Let me see if I can help.
Since the other keypad functions light and it is the start key not working, I would start by making sure the dishwasher door is securely shut. If the door is not making connection, the dishwasher will not start. Second, make sure the control lockout feature was not accidentally turned on. Press and hold the
key for 5 seconds to turn the control lock feature off (or on). If these do not cure the problem, the images below will help run a diagnostic test to get the dishwasher to provide the information needed. The second image will help with a keypad test if necessary. Once the diagnostic is complete, reply with the findings for further assistance. If you would feel more comfortable having a technician run diagnostics, you can schedule a technician here;
Sears Home Services