If you still have the original alarm siren then the siren may be coming to the end of its life and it’s trying to say good-by to you before it expires.
Is the chirping sound when the car is being locked or unlocked or is it only happening only when the door is physically opened?
Dec
Is the chirping sound when the car is being locked or unlocked or is it only happening only when the door is physically opened?
Dec
Best to unplug the siren, not sure which side it’s located on a right hand drive car but you will know from the chirp noise.
See… Alarm siren and battery placement - MBWorld.org Forums
The siren may still chirp for a while after you unplug it as it has back up batteries inside it, best to remove the unit from the car completely. The siren is the “brain” of the alarm system and not just a horn.
Replacement is around £90 from an MB dealer, you will need your VIN number to buy the correct unit, don’t buy second hand.
Dec
Edit; Cover the alarm siren plug with insulating tape after you unplug it to protect from moisture.
See… Alarm siren and battery placement - MBWorld.org Forums
The siren may still chirp for a while after you unplug it as it has back up batteries inside it, best to remove the unit from the car completely. The siren is the “brain” of the alarm system and not just a horn.
Replacement is around £90 from an MB dealer, you will need your VIN number to buy the correct unit, don’t buy second hand.
Dec
Edit; Cover the alarm siren plug with insulating tape after you unplug it to protect from moisture.
Last edited:
kolobos
Active Member
It's definitely the SIREN in my opinion, I have an 04 S320 and when I locked my doors it was alarming and even randomly flashes the indicators when parked. The doors were auto locking within seconds and all sorts of other issues.
I had mine replaced at my local Mercedes specialist garage (not Mercedes themselves) and it was £180 fitted as it also had to be coded to the car, another attempt by Mercedes to stop you from fitting yourself? On the plus side they used STAR diagnosis and cleared all the faults generated by the faulty siren.
The siren has two MH batteries that eventually leak and the acid destroys the circuit board, hence your problems.
Steve...
I had mine replaced at my local Mercedes specialist garage (not Mercedes themselves) and it was £180 fitted as it also had to be coded to the car, another attempt by Mercedes to stop you from fitting yourself? On the plus side they used STAR diagnosis and cleared all the faults generated by the faulty siren.
The siren has two MH batteries that eventually leak and the acid destroys the circuit board, hence your problems.
Steve...
horgantrevor
MB Enthusiast
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- w202 c43 & w210 E220 CDI estate w219 W221
i fitted one recently to a w211 no coding required i did put on star and cleared the faults
it under passenger arch remove trim and you will see it
it under passenger arch remove trim and you will see it
Mine was replaced last week. Started going off randomly, and the key fob buttons or starting the engine would not stop it. They apparently have two cheap Varta batteries soldered onto the circuit board, and it is quite common for them to leak. Retail price £84.51 + Vat from Mercedes. My Indie supplied and fitted it for £120 inc vat. Located in a metal bracket behind the drivers side front wheel arch liner on RHD W211's. The new one cheeps once when you unlock and three times when you lock. Apparently this can be silenced with Star. Not loud though.
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kolobos
Active Member
If its not loud enough why would you want it silencing? It might not be loud but its an indication that the alarm is activated or deactivated! If a door is not shut properly it only chirps twice, if the alarm is silent you might not be aware. My opinions really and yes it could do to be a bit louder.
Steve...
Just tried that, your right Steve, on my car if a door is not shut properly then the hazard lights don’t flash at all and only 2 chirps as opposed to the usual 3 chirps from the alarm siren.
Dec
The alarm is silent in most countries. To enable the 'beep beep beep' the SAM unit can be set to 'Netherlands' country settings. The old alarm was silent, just flashing the indicators, which I prefer. The noise is subtle enough though that I will not bother to get it silenced. If it were a louder 'chirp' then I definitely would. The new alarm units are coded with the 'beep' as default setting.
