Hi @lindsayprice
Is the compressor motor running?
The humming sound could be the compressor trying to start and failing to do so. It is the compressor that pumps the refrigerant through the sealed system to cool down the temperatures in the compartments.
If you can't hear it, feel the motor with the back of your hand to feel if it is vibrating or even if it is warm/hot. Be careful in case it is hot.
If it is not operating when it should be, there could be several reasons for this to happen:
or worst case a faulty compressor.
The supplier linked above was only to show you the parts and their locations as they are all situated near each other at the back at the bottom of the refrigerator.
If you decide to try changing either the 1st or 2nd part mentioned (do this with the power disconnected from the refrigerator), then search online for the manufacturer's part number for the part, shown in the links, to find suppliers that suit you best.
If the problem is the compressor, then depending on your location, you may need the services of a licensed repairer to fix it. This is due to the the environmental regulations regarding the handling of refrigerant gases, as the sealed system in the refrigerator would have to be accessed to test/remove/replace the compressor.