if the fan still doesn't kick on at that point. The sensor in the thermostat housing probly took a shit. It's responcibility is to check the temp & if it hits a certain temp it's supposed to kick the fan on.

easy way to test & find out if the fan actually functions or not would be to unplug that sensor & jump the 2 pins together with an extra peice of wire. If the fan kicks on then the fan works. If it doesn't then the fan is broke. But like i said, it's supposed to sence temp & turn it on by it self.