To find it, you should:
* Consult your owner's manual: This is the best place to start. The manual will have a diagram showing the location of the plug.
* Look near the engine block: It's usually located somewhere on the lower front of the engine block, often near the oil pan or coolant drain plug. It might be tucked away in a somewhat difficult-to-reach spot.
* Check the driver's side: It's more commonly located on the driver's side of the vehicle.
* Examine the front bumper area: In some models, the cord may run through a grommet or opening in the front bumper or splash guard.
* Use an online forum: Search for your specific year, make, and model of Ford diesel on an online forum dedicated to Ford vehicles (like Ford-trucks.com or similar). Other owners may have posted pictures or discussed the location of their engine block heater.
Without knowing the specific year, make, and model of your Ford diesel, I cannot provide a more precise answer.