To locate the air intake temperature sensor on a car, remove the air cleaner cover from the engine, and then locate the tube that sits below the air intake manifold. The air intake temperature sensor is plugged into that tube and looks like a silver cylinder; it also resembles a spark plug.
Before attempting to locate the air intake temperature sensor, make sure to let the vehicle cool down if it was recently running; burn injuries can result from touching a hot engine. The air cleaner cover sits on the top of the engine. To remove it, loosen the nut on the top of the cover with a wrench, remove the air hoses from the sides of the cover by hand, and lift the cover straight up off of the engine.
Air intake temperature sensors often get jarred loose or otherwise malfunction over time; when this happens, the dashboard's Check Engine light usually comes on as a result. These sensors are responsible for monitoring the temperature of the air entering the engine; the tip of the sensor is usually exposed to this air. The sensor itself is actually a thermistor, which means its electrical resistance is altered when the temperature changes.