Please help if you can, I have a o4 C220 and when parked up the hazards flash fast, the only way to stop it was to unlock the car remotely, this was a little on off problem for about 2 weeks, as off yesterday the remote central locking has failed, I have changed both sets batteries in the key fobs, still not working, therefore my local garage have changed the alarm unit at a cost of £83 plus fitting and still no central remote locking, any answers

 

kinda sounds to me like the alarm is going off but the siren isn't sounding. maybe you have a broken door jam switch. try using the PANIC button on the remote, see if it does the same thing, or if the horn sounds as it supposed to.