It would seem you have the wrong version headlight, and they are not interchangeable. You risk causing damage to the BCM depending on how the replacement light is configured. There are at least 4 or more different headlight versions for the Mondeo Mk4, you need to check the full part number and make sure the new one is the same.
For example, if your original light is part number 7S71-13K060-AB then a replacement must be the same part, the only letter that can be different is the last one.
So you could use 7S71-13K060-AC, 7S71-13K060-AD, 7S71-13K060-AE. However you could not use an older unit like 7S71-13K060-AA.