If you know the Ford-assigned door code, enter it and the driver door will unlock. within 2 (maybe 5 but lets go with 2) seconds press the 1-2 key and then any combo of 5 digits (say 73146 for example)
There will be no "success" indication. Lock the car (or don't), then try the code you just entered (73146) if it unlocks the driver door you have correctly set the personal code. If it did not work you probably took too long between hitting one of the numbers - I think it gives you 10 seconds per number, but that may vary by model. To change it follow the same process, the new one will replace any prior personal code. To erase the personal code do everything up to pressing the 1-2 key then don't press any numbers for 1 minute.
There are detailed instructions on this in the owners manual for most F/L/M vehicles that had this as an option. It will have better instructions and also model-specific details on where the key code is posted on the car.
ED: Oh and incase it looks confusing, you do not have to enter the code to lock the doors. When exiting the vehicle just press the last two buttons (7-8 + 9-0)
ALL CODES are 5 digits - the Ford one, and any one you try to set.
