Had this problem today MH not used since mid December key fob not unlocking doors long story short ford introduced rechargeable batteries in the blue fobs and are charged when engine is running if not used for some time these batteries go flat and lock you out so be-aware this is completely new to me got in through the Hab door ran the engine 10 mins all ok this is a 13 plate transit, there is a fix using new battery and new fob case old case is destroyed when getting at the battery all is revealed on Mr Google
Thought this may be of help
Thought this may be of help