The Throttle Position Sensor (TPS) on a 2003 Dodge Durango is located on the throttle body. The throttle body itself is typically found on the intake manifold, near the engine's air intake. It's a relatively small sensor, usually mounted on the side of the throttle body, and will have a wiring harness connected to it.
To be precise, you'll need to consult a repair manual specific to your 2003 Durango's engine (e.g., 3.7L, 4.7L, or 5.9L). The exact location on the throttle body might vary slightly depending on the engine. A visual inspection with the air intake removed will readily reveal it.
