locking buttons

afternoon folks, my door lucking buttons seem to have become a bit temperamental. none of the three (two door and boot) buttons were not working at this morning. I would have put it down to a dodgy button for all three at once seems a bit strange? does anyne have any suggestions? cheers.
 
Keycard not being recognised? Maybe the battery is getting low as the car won't lock if it can't detect the card nearby.
 
thats what i'm hoping, i think, it has come up a few times recently as teh card not being recognised, but i put it down to being under my mobile phone. The buttons on teh card still work perfectly, ill swap the battery and go from there
 
I've found that you do need a strong battery for the auto unlock to work, whereas the buttons work just fine on the card.

Change the battery first, I did get a new card out of Renault at one stage as they accepted that mine had gone faulty so they aren't perfect.

Theres also been talk of some form of induction charging by placing it in the slot in your car and it charging some kind of second battery, though I've never actually looked in to it so dunno if its a myth or not.