Dave Beard

Hi guys, this is my first post so please excuse me if appears to be a daft question. I have a 2003 freelander 1 td4 kalahari. The central locking has started to play up! I don't use the key fob as that appears to work only sometimes when it feels like it... Using the key worked fine but now the passenger door does not lock when you turn the key. Opening the door results in the alarm going off. Is there a quick fix for this passenger door lock or do I require a replacement. TIA Dave