W215 Alarm randomly triggering

[jinkazama]

So the alarm started going off randomly at night, had the alarm siren replaced but did not solve the issue. This is currently disconnected. Upon locking the car the alarm triggers 80% of the time ( flashing indicators ), if the car is then unlocked and locked straight away with the fob, it stops. So two cycles of locking cures the issue.

STAR says the only fault is the alarm siren is disconnected. It does not point to any micro switches or such. I have also switched the motion sensor off but it still triggers on locking 1st time.

Any ideas ?

 

[grober]

Not sure about how the alarm system works on your particular car but it might be something mechanical- on first locking something is not moving quite enough to make contact to send a "locked " signal- repeat the exercise and it does?? Have you tried locking/unlocking several more times to see if you can get the fault to recurr. If you put in your exact age and model in might help.

 

[jinkazama]

Thanks, it's a 2003 CL55 Kompressor. The mechanical idea is a good one, I'll see. The fault is reoccuring as it's something I've lived with for over a year now.