The lights in the upper food section of our Sub Zero 550 (circa 1990) are malfunctioning.
3 weeks ago the food section stopped cooling. The lower freezer was not affected and was working normally. The lights were still working at that time.
I called a service tech (all makes), and the tech replaced the thermostat and condenser fan (fan was apparently wobbling and about to fail). He also replaced the light bulbs which had burned out from all the handling while being serviced. After the repair was done, the food section was cooling again and all the lights were working.
The following morning, the lights would not always come on when opening the door, or they would come on randomly on their own. In those random times, you can hear something clicking somewhere inside the fridge as the lights turn on or off by themselves. Soon after, the backlights for the temperature control knobs failed one after the other and now no longer work at all (ie. they still work for adjusting temperature, just no lights).
The tech has come back several times, and has replaced the door switch for the light, the bulbs for the control knobs, and the light terminator. Nothing has worked. He said he would be contacting Sub Zero and ask why but these are CORVID-19 times and it is difficult to reach anyone.
Does anyone know what is going on? Any help is appreciated. Thanks in advance.