Topjoe9

Hi all.
My 3dr Cosworth stereo volume has started going up to full by itself when I just turn it up slightly. Also when this happens the drivers central locking actuator clicks.
Does anyone know what could be causing this or know of a wiring diagram for the stereo system.
I'd assume the wiring for the central locking and stereo would be totally independent of each other!
Any help much appreciated.
Cheers
Derek.