I have a Bosch Classixx Fridge Freezer which appears to have a failed interior light unit. To test this I have taken the light bulb out and tested it in another Bosch unit and it works without a problem. The interior door switch has no effect and does not switch on the light. I have spoken with Bosch who have quoted a price and a part number for the replacement light unit, but will not provide me with instructions on how to install this unit. Does anyone have the technical instructions on how to replace the light unit.