Central locking issue

The central locking on my 2003 Volvo V70 D5 (with 83k miles on the clock) does not work. This was an intermittent fault but now seems to have become permanent.

All doors and the tailgate will lock with the key, but no alarm is set. The high level courtesy lights no longer work when opening the doors or even trying to switch them on using the adjacent switches, and I know these are linked to the central locking system. The footwell lights are working.

I think there is a relay on the central control module in the driver’s footwell, but do not know which one. The key fob batteries are good and I have checked all fuses relating to interior lights or central locking, and tried wiggling the cables between door and body.

I have just had the dash module repaired for the usual V70 reasons – a new processor was fitted to the board and the battery was disconnected for a week. Prior to this, I thought the central locking problem might be related, but as the dash now seems okay I guess I have two separate problems. Tim Shord According to the data I have, the central locking relay should be located in the rear of the vehicle below the floor towards the nearside. On one side of the relay control box there should be a line of 10 relay sockets, but not all will have a relay. The central locking relay should be the fifth one in line counting from the fixed end of the box; the relay number should be K31L.

With the relay box located in the rear luggage area, it is also possible that moisture has got into the system. A thorough check of the connections would be the best first step.