Neither the condenser fan or the freezer evaporator fan is working. The fridge still cools, but not cold or freezing. Is there a switch or relay that controls both? This is a GE Model GTS18HCMDRWW.

Yah, there are control relays for when they are to kick on. Is there ice building up in the freezer? If so, ice may be keeping the blades from moving; and possibly the heating element for de-frost mode is out (provided this isn't a very old frige).

Check/clean all connections to the fan for the compressor. If it isn't encouraged by the fan to cool, it will lock up.

XenoSapien

THe door switch would be a good place to start. If it is defective it will not make contact and the other componets never ger the call for cool.