To locate it precisely:
1. Consult your owner's manual: This is the best resource for the exact location for your specific vehicle.
2. Look closely in the front of the engine bay: Pay attention to the area around the lower radiator hose and the engine block itself. The cord may be somewhat hidden behind other components.
3. Check near the driver's side: It's often placed more towards the driver's side of the engine compartment.
If you still can't find it after checking these areas, a visual inspection of your Focus's specific engine may be difficult and potentially dangerous if you're unfamiliar with car maintenance. In that case, it is best to take it to a mechanic or dealership for assistance.