MacBook Air Only Charges Through Car Socket (12V)

Hi,

I have a 2011 13" MacBook Air that seems to only like to charge itself when plugged into my car 12V socket.

It won't charge from my external 27" Apple Display, nor from the genuine Apple Charger that came with it.

I thought it might have been the I/O Board, so I replaced it. It charged once from the external Apple Display and then the next time plugged it in it wouldn't charge.

I ran Coconut Battery on it to see if the battery was at fault but the status was Good with no problems know.

I have reset the SMC/PRAM all the usual stuff relating to not charging, but no luck

Any one else have similar problems?