You need to calm down there a little bit and relax there son. Maybe get some spelling and grammar lessons as well. j/k
Why would you wire it to a switch. It should go from the sensor on the block to a relay. The relay will have a direct feed from the battery or distribution block through a short stop (resetting breaker basically). Upon the sensor tripping at the proper temp it triggers the relay (in a sense like your hard wired switch) which then provides power for the fan. Most e-fans on startup can take around 40+ Amps then drop to about 20'ish to just run.
If the fan stopped running all of a sudden look for a short (causing the breaker to trip), or the in block sensor has failed. The in block sensor (if memory serves) is at the front of the block and has a single wire coming off of it. Or is that the gauge sensor in that spot? Crap, I can't remember which and I don't have my book handy. It should be easy enough to back trace the wires to the sensor. Testing one of those sensors is easy, it is just a dielectric switch, test it with a VOM and hot water. It will drop to 0 Ohms across the body to the pin when dropped in hot water (boiling works).
