To install a temperature sending unit, open the hood of a vehicle, find the temperature sending unit, disconnect the lead wire from the sending unit's terminal, pry out the sensor, fix a new sensor in place, and reconnect the lead wire. Required tools include a screwdriver, ratchet, torque wrench and deep socket set. Read the repair manual before starting the installation.
Open the hood, secure it with a hood support rod, and find the temperature sending unit. The sensor is generally positioned at the front or on the side of the engine. Use a drop light to find it. If necessary, pry off the fan shroud to gain access to the sensor.
Depending with the model, use a flathead screwdriver to remove the clips that hold the sensor in place, taking care not to break the tabs, unplug the lead wire from the terminal of the sensor, and set the wire aside. Unfasten the sensor with a ratchet and deep socket, increasing force slowly until it comes off. Use a clean rag to clean debris and dirt off the threads and area.
Place the new temperature sending unit in the threads. Rotate it with your fingers, and then twist with your hand. Use a torque wrench to securely tighten the sensor in place. Clean the end of the lead wire, and tightly connect it to the terminal of the sensor. Start the car, wait for a few minutes, and test the installation.