W203 alarm siren not working

[amazighman]

Good evening.

I am having trouble with my alarm siren not working on my w203 ,lights flash but no sound.
Changed the alarm ( new one is working as removed from my other car) still no luck.
No lights on the switches on the dash to deactivate the alarm for towing etc.

Could it be the module for the alarm or fuse , checked fuse 41 8 9 all good

 

[whitenemesis]

In what way is the alarm siren 'not working'?

 

[IanW]

When you tried the one from your other car, did you bolt it into place for the test, or just hook up the connector?
IIRC, the alarm module is earthed through the mounting bolt.

Ian.

 

[amazighman]

When you tried the one from your other car, did you bolt it into place for the test, or just hook up the connector?
IIRC, the alarm module is earthed through the mounting bolt.

Ia

Are you sure its earther through the bracket? As when i removed the old one the thread insert on the plastic siren housing came off with the screw , didn't notice any connection from there to the alarm electric board

Picture i found online on right side is the half of the housing where it bolts into the bracket. No sign of earth connection to the circuit board
.
I tried holding the metal thread insert touching against the metal mounting screw still nothing as. i thought it may be earthed , did that because I painted the bracket

 

[amazighman]

In what way is the alarm siren 'not working'?

Only lights flash but no sound

 

[Petrol Pete]

These things are notoriously crap , there is a good chance the used one you fitted is also faulty. When a fault occurs it is normally the unit itself as it is pretty 'stand alone' with it's own power and sounder.

When they go wrong they can feedback all sorts of weird and wonderful faults back into the car , I have experienced this myself on a W203 (not my C55....yet) . In that case we just disconnected it and forgot about it.

 

[IanW]

Are you sure its earther through the bracket? As when i removed the old one the thread insert on the plastic siren housing came off with the screw , didn't notice any connection from there to the alarm electric board

I must be mistaken then. Since the siren has a 3 pin connector, that would make them +12v, ground and a single signal line - which controls a lot of electronics on the siren board. Unfortunately, I threw away the old siren bits, so I can't check continuity.
Ian.

 

[amazighman]

These things are notoriously crap , there is a good chance the used one you fitted is also faulty. When a fault occurs it is normally the unit itself as it is pretty 'stand alone' with it's own power and sounder.

When they go wrong they can feedback all sorts of weird and wonderful faults back into the car , I have experienced this myself on a W203 (not my C55....yet) . In that case we just disconnected it and forgot about it.

I agree they are rubbish.
I took a working one from my W211 and fitted it to the W203 and still no joy.
I bought a second hand latest alarm MB produced which has a yellow sticker part A2198203226 still no working alarm

 

[amazighman]

Still doesn't work with the replacement module