If you are referring to the fan installed behind the refrigerator, there is a thermal switch mounted on the upper rear fins that will cycle the fan on and off as needed. There is also a fuse for the fan and thermal switch circuit that may have blown.
I had to replace a failed fan behind my Dometic refrigerator. Dometic used a cheap sleeve bearing fan. Fortunately, it is a commonly available 120mm 12 volt power supply fan. The replacement fan I used was a Delta AFB1212L dual ball bearing server fan that is designed to operate 24/7. The fan draws so little power, I simply wired it to operate whenever the refrigerator is on, bypassing the thermal switch (one less thing to fail).
The new replacement Delta fan was about $9 on Ebay, and fit the existing bracket behind the refrigerator perfectly.
2010 Georgetown 373
2013 Jeep Wrangler