The control panel is held in by a steel retainer at the rear of the unit, so the door panel has to be removed to get the control panel off of the door panel. Once free from the door panel, I opened up the case of the control, turned the lights on and wiggled the bulbs until I found out which one had the bad solder (they are wheatlamps soldered onto the circuit board and are wired in series in groups, so if one lamp burns out or has a bad connection another lamp will also go out on the panel with the bad one). Once I found the bulb causing the problem, I put a dab of solder on my iron and touched it to the solder joints on the circuit board where the lamp was mounted to remelt the original solder. You only need to hold the iron there long enough to melt the original solder, then pull the iron away. No more bad connection, and it has been working flawlessly ever since!