2003 Citroen Relay 2.2 HDI central locking not working?

Hi All Recently picked up a 2003 2.2 HDi Citroen Relay. The central locking doesn't work using the remote key, either by remote or by turning the
key in any lock? I dont have a manual or wiring diagram and apart from checking the fuses, which are all fine, I'm not sure where to start? Is c/locking controlled by a relay? Any ideas on where to start looking/testing? I did the BSI reset thing but it made no difference. Many thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.