Cannot access diagnostic mode

My dryer is actually a Whirlpool but very similar to this model. The door lock is on but will not unlock either by using the 3 sec. button hold procedure of the machine or by unplugging the machine for up to 15 mins. We have removed the top and tried disconnecting and reconnecting some of the wires to the electronics board that see like they would control the door lock. Of course we cannot access the diagnostic mode because none of the buttons will work while the door is locked. Help!