New old topic Bosch KGU3201GB Fridge Freezer problem

[IPCAM]

Maybe the last one living, but I have a venerable Bosch KGU3201GB Fridge/Freezer that has only just started to play up. The freezer is working well and will easily reach and hold the -18 C temperature. However, the fridge has recently started to misbehave. A few weeks ago it started to cycle between +2 and +7 C. I took out the fridge compartment thermistor and it started to show the E1 fault and recovered when I replaced it, so I think that is OK. I took everything out of both compartments and took the cover off the back wall of the freezer compartment. There was no sign of ice build up, and actually not much frost at all, but I left it to warm up anyway. When I switched it back on, the fridge reached +2 C and seemed to stay there for several days. Then yesterday it started to show the dreaded E2 error and slowly warmed up to room temp. I once again defrosted the whole thing and on switching back on, the E2 error was gone and the fridge indicated room temp. I have read old posts here and elsewhere about this particular model, and the E2 fault being due to the thermistor that is imbedded in the foam in the back wall being faulty or shorting out due to moisture. Unfortunately my model has no arrow indicating the whereabouts of this sensor as some posts say should be there. Any clues?
I would dearly like someone to solve this, or even explain it to me. For example, if the thermistor is indeed buried in the foam, how can it get wet? Why does defrosting seem to reset the fault, even though there is no ice buildup that I can see? How does the fridge compartment get cooled anyway on this model? There are NO vents in the fridge compartment for cool air to be blown up by the freezer fan! Now that it is cooling again I have looked inside the fridge compartment with a thermal imaging camera and it seems that the whole of the upper half of the back wall is cooling. How does this happen? Is some of the cooling fluid diverted from the evaporator??
Update. The back wall cooled to -22 C briefly, but now the E2 error is showing again.

[Author]

Posts