Refrigerator - Buzzing Noise
If you hear a buzzing sound coming from your refrigerator, it is most likely coming from the icemaker or water valve and is normal.
The icemaker will make rattling, humming, buzzing or vibrating sounds in the following situations:
The icemaker is filling with water. This would occur approximately every 1 hour to 1-1/2 hours.
The icemaker is turned on but the water supply to the icemaker is turned off. The buzzing noise would be be heard approximately every 15 minutes (every time the icemaker attempts to fill with water). Check to make sure the water supply line connected to the refrigerator is turned on. To keep this buzzing from occurring, make sure the icemaker is turned off if water is not connected to the refrigerator. Refrigerator - How to Turn Icemaker On or Off.
On models with the XWF filter (featured on many Bottom Freezer and Side-by-Side style refrigerators), you may a buzzing sound for 5 seconds about once every hour. It is caused by an isolation valve that is designed to help prevent major leaks from the filter.
Please view the following video about normal refrigerator noises: