I'd check the fan relays first then the temperature sensor and then the wiring going to and from the fan to the relay and to the main comp too especially the grounds.
Hope that helps and best of luck.By the way one way to try the relays is try switching a relay that's a non vital relay that has the same exact part number and check the sensor if you plug it out and the fan stops that more then likely is a internally shorted out or damaged temperature sensor.
