The annoying humming noise thatâs coming from your fridge could be caused by a number of problems, some of which are easy to solve, some of which youâll need a quality mechanic for, and some that will force you to replace the machine. Read on if you have a refrigerator making humming noises and you want to fix it. Sound coming from the back. If the humming sound is coming from the back of the fridge, itâs either due to your compressor or the motor fan. A broken compressor is a big deal, as your fridge wonât cool properly.