I recently had an issue in that my central locking failed and would only intermittently work if I use the remote very close to the door sensor, after some checks I found that fuse 8 in the boot had blown, I replaced fuse and it immediately failed. Fuse 8 supports a shared line with the alarm siren. and central locking.
The alarm siren is located behind the O/S wheel arch liner, a further check proved that there was a short within the siren causing the fuse failure. Just disconnected the siren and ordered a new siren from Merc a good few weeks ago. The central locking works perfectly. The siren is a special order (still on the way) or VOR as the parts assistant told me. I can't believe that the siren was positioned under a wheel arch. On the plus side it's quite easy to get to.
The alarm siren is located behind the O/S wheel arch liner, a further check proved that there was a short within the siren causing the fuse failure. Just disconnected the siren and ordered a new siren from Merc a good few weeks ago. The central locking works perfectly. The siren is a special order (still on the way) or VOR as the parts assistant told me. I can't believe that the siren was positioned under a wheel arch. On the plus side it's quite easy to get to.