To find it definitively, you will need:
* Your Mondeo's specific transmission type: This information should be on your vehicle's registration documents or in the owner's manual. Knowing this is crucial.
* A repair manual or online diagrams: A repair manual specific to your year and model Mondeo will show the exact location. Many online resources (some free, some paid) provide diagrams. Search for "[Your Mondeo Transmission Type] VSS location."
Without knowing the transmission type, a precise location cannot be given. It's generally found on the transmission case, often near one of the axles or the transmission output shaft, but the precise position varies. Expect it to be a sensor with a single electrical connector.
Caution: Working on your car's transmission can be complex. If you're not comfortable with car repairs, it's best to take your Mondeo to a qualified mechanic.