Where is the engine coolant sensor located on a 2003 Saturn Ion.?

The Engine Coolant Temperature (ECT) sensor on a 2003 Saturn Ion is typically located on the engine block, near the thermostat housing. However, the exact location can vary slightly depending on the engine (2.2L or 2.4L). It's usually a single-wire sensor, and sometimes has a small connector.

To be certain, you'll need to:

1. Consult your owner's manual: This is the best resource as it will have a diagram showing the exact location.

2. Use a repair manual: A Haynes or Chilton manual for your specific year and model Saturn Ion will have detailed diagrams and instructions.

3. Search online: Use your vehicle's year, make, model, and "ECT sensor location" in a search engine (like Google or Bing) along with images. This might reveal photos showing the sensor's position on similar vehicles.

Caution: The engine will be hot after running. Allow it to cool completely before attempting to locate the sensor.