Q: I have a 2005 vw jetta 2.5. Trying to find location of Coolant Temperature Sensor?

As you face the front of the car, the coolant temperature sensor is on the right side of the top of the engine. You will see a clip that holds the sensor to the engine mounting surface. Look for a plastic top on the sensor (gray or black) and a two-wire terminal wiring harness plugged into the plastic top. The sensor is merely one component in the radiator fan circuit and may not account for the misoperation of the fan. There is also a relay and that relay could simply be stuck closed and/or the circuit commanding the relay could be always powered on due to a short circuit. In any event, all components should be tested prior to condemning them, both to save money and speed the diagnostic. If you desire that a mechanic resolve this, simply request an electrical component diagnostic. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.