Ok, had an M.O.T. 3 weeks ago on my 300tdi. they'd missed plugging a couple of warning dash indicators after some right inner wing welding.

Accidently unlocked with the key instead of the fob and the alarm went off, kinda.....

The hazards are flashing, the immobiliser works, but the horn doesnt sound, however it works normally.

i'm gonna take a drastic guess and say that they unplugged something, but anyone got any ideas as to what, or what might be the problem if not,

cheers, bex and tom

Did the alarm sound before? My 300TDi doesn't sound the horn but a seperate alarm. The alarm siren can be turned off.