[carsonmx114]

unplug the big silver relay in the fuse box. the relay is probably sticking. is the relay clicks when you unplug it and plug it back in the thermo switch is bad. if the relay doesn't click but the fan goes off the contacts in the relay are stuck. when the relay cools off it is probably unsticking itself. also you could try tapping it with a screwdriver handle while the fan's running.