Our Amana side-by-side model SXD524VW (Belgium supplied and installed)stopped working. Lights still work. Some light noise (compressor?) can be heard. But it is warming up. Icleaned all out. It was really dirty after 8 years operation; sorry :-( Is there a manual for this unit? By the way, there is a small black box at the front/bottom in the middle with a knob on it that will only permit turning clock-wise. What is it for?