Seems to be over cooling and ice builds up behind the salad tray. If the ambient temp cools then the fridge seems to over cool so have been turning the thermostat down to alleviate the ice build up as summer heads into winter. Stat now turned all the way down. Circuit diagram attached but not sure how much I can do as appliance is built in. Thank you Arthur
The fact it has a heater and a fan means it’s a frost free type. Possible issues all revolve around the evaporator. Ice build up caused by failure of fan, heater or ice sensor.
I had it with a fridge/freezer I had a maintenance contract so each time there was a problem called out a fridge guy, but would try defrosting first, then one time did not defrost first and the guy condemned the whole unit as it seems the insulation had failed and as the ice builds up in the insulation it causes uneven temperature. It was nothing to do with motor and control gear, it was carcass at fault. A full defrost would melt all the ice, and it would seem to work A1 for a few weeks, hope yours is not that, but try a full defrost, and see what it is like after.