Internal freezer fan won't come on?

Hi, I have a Westinghouse freezer model number FJ303Q-L its red light came on and the stuff in the freezer seemed to be defrosting. I emptied it and left it for a week,turned it on, compressor comes on, red light comes on, fan does not come on, it cools down but the fan is not on and circulating the defrost timer seems to be working. Is this the thermostat or something else. Is the fan connected to the thermostat? Any ideas?