Clicking noise comes from the top right side of the refrigerator just inside the door. I think it's coming from the control panel. I've already replaced the start device/relay, overload breaker, and condenser fan. Refrigerator worked for a while each time but after a few days clicking returned. Is there a way to test the control panel, etc? If yes, how do I remove it and how do I test it? Or, if you have another idea, please advise.

Simon,

Why do you say it's the ADC board? What does the adaptive defrost control board have to do with the clicking noise? Are there any diagnostics I can perform to make sure?

Also, I'm not sure what the escutcheon is you referred to, nor do I see any knobs I should take off. Isn't the control panel at the top where the light bulb is screwed in? I see 4 screws, but there are also 2 brass nuts with washers that seem to be holding the entire assembly to the inside top of the cabinet. I appreciate any help you can give.

I replaced the ADC and while I was at it thought I'd better test the defrost thermostat and the heater element for continuity. The heater element checked out fine, but the thermostat was partly separated, so I replaced it. Put everything back together, and voila! Refrigerator is cold again! Thanks so much for your help, Simon!