Peugeot 306- No Central Locking? - Mos
I have recently bought a 306. Until today everything has been fine. I went to lock the car with the remote control on the key this morning, and nothing happened. The battery is fine. When I try and lock the doors manually with the key the central locking doesn’t work either. What is more puzzling is that when I enter the car the interior courtesy lights flash! The car starts but I have no idea how to stop the flashing lights and engage the central locking again. I would be grateful of any advice.
Peugeot 306- No Central Locking? - DL
Try a search, it has been documented at length here quite recently.

In a nutshell, it'll probably be broken wire(s) between the pillar and the door, usually on the driver's door.

Value my car