It appears I have a loose bulb or bad solder joint for the HVAC control panel lights. Part of the panel is dark but I can tap on it and the dark area will light up. Sometimes just hitting a bump will cause it to fully illuminate. It appears to be a bulb near the center of the panel. If I turn the lights off and back on sometimes they will all illuminate and sometimes not, but a tap will cause them to come on. Does this sound like a bulb not making good contact or a bad solder joint?