Where is the engine coolant temperature sensor on a 1990 Ford F150?

The exact location of the engine coolant temperature (ECT) sensor on a 1990 Ford F-150 varies slightly depending on the engine (e.g., 5.0L, 5.8L, etc.). However, it's almost always located in the intake manifold or in the engine block itself, near the thermostat housing.

To be certain:

1. Consult your owner's manual: This is the best resource for the specific location on your truck.

2. Look at a repair manual: A Haynes or Chilton manual for your specific year and engine will have diagrams showing the sensor's location.

3. Use an online parts diagram: Many websites like AutoZone or RockAuto allow you to select your vehicle's year, make, model, and engine to view diagrams showing parts locations. Look for a diagram showing the engine's cooling system.

The sensor itself is usually a one-wire or two-wire sensor, and relatively small. It will likely have a single or dual-prong electrical connector attached. Once you locate the thermostat housing, look closely in that immediate vicinity for a sensor fitting that description. Be cautious when working near hot engine components. Let the engine cool completely before attempting this.