Ok guys, so i've had this happen twice now. I'll take my lunch break and go sit in my car, i turn it on (not start it) and listen to the radio. The engine is cold as its been sitting about 4 hours. After about 10 to 15 minutes the fan comes on. The only thing i can think of is resistance in the temp sensor causeing it to get hot and turn on the fan. Does this sound right or has anyone else ever heard of somethin like this?

 

You can check the wiring for the intake coolant temp sensor and the power switching wire (will be a ground) for the relay. You can try replacing the coolant sensor as they are cheap anyway. Something is tripping the relay it is either the switching wire (ground) grounding out between the relay and ecm or a bad ground from the sensor to ecm or a bad sensor.