Alarm Hazards Flashing But No Siren ?

[Aletank]

I've noticed on about 3 occasions now that when I have locked the car and looked out of the window, the hazzard lights are flashing but no alarm siren.
The siren works as I locked my girlfriend in the car the other week and the siren went off - Maybe that has something to do with this.
Thanks For Any Ideas/thoughts

 

[BlackC55]

I suspect the siren is faulty.

 

[Aletank]

Thanks for the reply
What would be triggering the alarm though ? all doors etc are closed/locked.
Would a STAR machine detect a fault ?
Thanks

 

[andy27168]

Hi,
These are quite a common failure, causing these symptoms, it is normally attributed to the back-up battery in the siren failling.
You could try turning off your interior movemnt sensors as you get out on the off chance you have some small creepy crawly setting it off but my money would be on the siren being U/S.

 

[Aletank]

Hi,
These are quite a common failure, causing these symptoms, it is normally attributed to the back-up battery in the siren failling.
You could try turning off your interior movemnt sensors as you get out on the off chance you have some small creepy crawly setting it off but my money would be on the siren being U/S.

Thanks for that - Any idea how to change the siren battery or how to access the siren etc ?

 

[andy27168]

The battery cannot be changed, though if you are careful using a knife and score around the edge of the siren whilst having released the screws you can sometimes get them apart, but to be honest It's not worth the effort as the battery can leak on the circuit board causing damage.

 

[Aletank]

I found this thread here with all the information needed http://www.mbclub.co.uk/forums/electronics/86238-indicators-fast-flashing-no-apparent-reason.html
Anyway I've had the Siren replaced today.
Thanks guys