w163 ml350 Alarm / Chirping / Beeping Issue whilst driving

[hamazz]

so got a problem on our 2004 ml350,
randomly the alarm will trigger during the day or night, or what we think is the alarm unit,

this will also happen randomly whilst driving, which makes us think its not the alarm unit,

done a vin search and the car has the 551 option for the anti theft system,
there is no fuse for the alarm in F48 or relay K31

Tried to disconnect the trip computer unit fully yesterday, but we still had the same issue today, where it beeps randomly whilst driving and whilst parked, so thinking it is something else

some threads suggest possibly the ebox fan ( ecu / fuse fan)

Anyone have any ideas, as to what might be causing this random alarm chirping

Hamazz

 

[AMGeed]

It's more than likely the internal batteries in the alarm siren have either leaked onto the pcb, or have failed.
You need a new alarm siren. I believe it is located under the wiper mechanism on an ML.

The siren should be around £100 and is easy to change once located. Its plug and play with no coding required.

 

[hamazz]

thanks for the reply, however as there is no fuse or relay for the alarm in the fusebox?
how would the siren be the issue? as you can normally bypass this issue by removing the fuse or disconnecting the unit?

 

[hamazz]

also if i force trigger the alarm, by locking it whilst inside then opening the door or jingle the keys by the trip computer, the lights flash as the alarm has been triggered but no sound at all..

 

[Abb]

As above, the siren is the most likely culprit. It is a very common fault with MBs of this era, to be sure you could always just unplug the unit (which is normally under one of the inner wheel arches) and see how you get on.

Again, as above, it is around £100 from the stealers and is a straight forward fix. Don't try and work out why it does what it does, once the internal batteries leak, they play havoc with the alarm system.

 

[Deletedmember130310]

thanks for the reply, however as there is no fuse or relay for the alarm in the fusebox?
how would the siren be the issue? as you can normally bypass this issue by removing the fuse or disconnecting the unit?

i believe most sirens have built in battery so the ne'er do wells can't silence the alarm by simply removing a fuse...