central locking on td5 series 2

Hi folks am newbie here. Have got a disco td5 series 2 on v reg and central locking playing up. Cant unlock anydoors using keyfob and only drivers door will unlock by key. The switch on the dash doesnt do anything, the doors can be unlocked pulling the interior handles twice although the drivers rear door wont unlock either way. When locking, doors will lock on keyfob most of time but deffinately by using key. Any suggestions will appreciated cheers

There are 2 bits to the central locking. The normal lock unlock motor. And the deadlock motor (super lock). When you lock the car the deadlock comes on forcing the lock if it has not already happened. However on unlock, all it does is remove the deadlock, the other motor does the actual unlocking.

The deadlock does not work on the internal switch.

They all share the same fuse, so give that the deadlock motors work, it won;t be a fuse.

So it sounds like the normal motor is not working. Now all doors are wired in parallel. So if your very unlucky its possible all locks have failed. But more likely some other issue. There are some relays in the main fusebox in the drivers footwell (controlled by the IDM). One of these might be faulty, or the IDM might be faulty and is not trying to turn the relay on.

Its also possible there could be a BCU fault that is not telling the IDM to turn a relay on. But I'd start by checking the relays. Press the lock unlock button and see if you can hear them click.

The wiring diagram is missing the relay numbers, so I can't tell you which ones they are.