Hello My name is Ian ~ I am not on the site constantly so please be patient whilst waiting for responses to you queries
Can I assume this is coming from the freezer area and does it stop when you open the freezer door?
OK hold on a second whilst I check the parts diagram
can you give me the product code it should start 90 or FA which will be on the rating plate, it appears that perhaps this unit is not a UK model?
Is the compressor housing covered in or can you get access to it?
OK that would explain why all the instructions were in I think Spanish and Arabic. OK the thing on the back is the defrost timer, it is a little electric control that switches the unit off for a period of about 20 minutes every 8~12 hours to allow the appliance to defrost any formed ice and allow it to work at optimum performance.
These tend to get a little noisy after time but are readily available and easy to change. Hope this information has helped you, if so kindly rate my service using the smiley faces below. You can continue to ask questions after rating at no extra cost ~ Ian
Yes it works on the amount of actual time that the compressor runs rather than an amount of day time. You can get universal defrost timers but just check that the contacts are the same as they tend to vary alittle. If you can now rate this I can shut the job down on the system, you can always come back for further advice at no charge. Have a good evening + Ian