My central locking stopped working the other day. There was no sound from the pump so I decided to investigate it. The pump now works again.
***The problem was corrosion of the contacts between the plug and the pegs on the pump***
Once i'd cleaned these up, the pump worked again. You can tell if it's corroded by the blue / white deposits when you take the socket out of the pump. I think this is caused by water / moisture.
I cleaned the pump pins by removing the pump casing to expose the pins. I used a stiff nylon brush to clean the plug.
Hope this can help other people with 'broken' central locking pumps.
I've only tried it a couple of times to make sure it works, time will show if it's a real fix.
Cheers!
*Edit*
Picture of pump contacts showing the deposits:
