I have that same refrigerator in my rv. It also has fans that blow air over the cooling fins and help move the warm air out the top vent. In my set-up the refrigerator is in the slide out, so the top vent is on the side of the rv. Once I remove the top vent cover, I have access to the limit switch that turns the fans on, as well as the fans themselves. The limit switch is on the cooling fins of the backside of the refrigerator. Its what senses the temperature and completes the circuit to turn the fans on. What im getting at, is that maybe the limit switch has broken and is now always completing the circuit. Or perhaps it has fallen onto something warmer making it turn the fans on all the time.
Another problem could be that the relay that powers the fans has malfunctioned as well. The relay is located near the bottom of the refrigerator. Behind the lower refrigerator vent.
And finally I would check where the power wires to the fan relay goes Into the power distribution block. Also near the bottom of the refrigerator.
I'm no expert in electronics and I'm not sure if I have explained this well enough for someone else to understand. I also may have not used the proper terminology in trying to explain how I understand the fan system works for the refrigerator.
I have attached an image of what the limit switch looks like. I had a problem last summer with the refrigerator fans not coming on at all, and to get me through my camping trip, I temporarily bypassed the limit switch and installed a 12v toggle switch in its place. That way I was able to turn the fans on and off manually as needed. Perhaps this is something you could do, so that you don't hear the fans running all the time.