Unfortunately without a model or E-Nr number it's going to be impossible to help.
Bosch have made so many different models.
If you've looked behind the salad drawers and there's nothing there then I'm sorry, I'll be unable to assist.
I've opted out for the time being so that the question is still open to all experts.
If you do find a model number I can opt back in.
good luck with it.
Sorry, the last post doesn't read very well.
The fault you describe is normally caused by a failure of one of the foamed in temperature sensors
Bosch do a kit that basically bypasses the sensor and all defrosting of the freezer is done on a time basis by the electronics
The part number for the kit is 491415
Click here for the part
It's worth a try before changing the appliance.
Hope this helps
Let me know how it goes.
It contains a connector to join wires and a sheet that tells you which wires to cut.
Save the cost of it. A roll of insulating tape is all you need.
Click here for the instructions
Good luck with it.
NTC = Negative Temperature Co-efficient.
As the temperature changes the resistance of the sensor changes.
The faulty sensor is used to detect when the defrost cycle has finished so telling the control board to turn off the defrost heater and turn on the compressor.
As it wasn't working properly (or at all) the machine went into defrost and stayed there.
Bypassing the sensor has now put the control board fully in control and the defrost is now a timed defrost.
Hope this explains it.
Glad it worked for you.
Thank you for the payment and the bonus, it is appreciated.