The reason I ask , is the manual for that year of Kuga mentions the headlamps only not the tail lights
Note: If you have switched autolamps
on, you can only switch the main beam
on when autolamps has switched the
The headlamps will come on and go off
automatically depending on the ambient
Hope you dont think I'm being cheeky , but on some older Fords the auto lights were often an option but switch / wiring was still installed even if not fitted . Is it possible you dont have them and are seeing the day time running lights which come on automatically on the front every time the car is started but the tail lights dont . You see quite a few people driving this way at night as the panel lights up and they think the lights are switched on . I just remembered this as I recently had someone in front of me in a traffic jam with no rear lights on and I flashed them and this was why Again apologies if not the case .
Just a thought . I always left faults like this to my auto electricians to solve but strange one , cant be sensor if front lights working . If anything comes to mind overnight I'll post it . Possibly light control module ? Scanning with ForScan or similar might show cause .