As i opened the fridge door there was a flash and a buzz . the light went out and the red warning light has now been on all day.. slowly defrosting . would this be just a fuse or ...? where are the fuses.. ? only replaced inside bulb a few weeks ago.. the appliance was here when we moved in .. there is no manual and the buttons/dials seem to have worn away. has been quite over-frosty lately.. door to fridge and freezer is opening and shutting all the time.