SL-Class (R230) 2003 -- 2012: Discussion on the SL500, SL550, SL600
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SL/R230: Alarm / Siren Issues : Goes off for no reason/Kills Battery FIX DIY..

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Old May 24, 2019 | 09:01 AM
  #26  
Frederick NL's Avatar
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2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
Originally Posted by John Macintosh
The wires from my PCB were about 6 inches (15 cm) long. This gives you ample length to solder them to your battery wires. The batteries fit very nicely under the siren (speaker portion) within the metal bracket that holds the siren module.
To what extend are the batteries exposed to the elements there? And vice versa: one day they will start puking out their gunk again. While inside that puck, the aggressive stuff at least didn’t affect surrounding materials (causing rust?). I think it’s a great idea to recuperate the siren, so just weighing the options.
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Old May 24, 2019 | 09:04 AM
  #27  
Frederick NL's Avatar
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2005 R 230 SL350 (M112 3.7). Sold the 1966 W113 230SL recently
Originally Posted by John Macintosh
Here is a revised document
link doesn’t work
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Old Apr 8, 2020 | 02:25 PM
  #28  
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2004 e500 4matic
Same problem!!

I have an 04 e500 and have been going crazy with that stupid siren going off!! Totally random and it would sound like it was dying if that makes sense. Never a steady just siren noise.
Anyway, at 1:00 this morning I had enough and took it out. No difference in the car and I can finally be stress and anxiety free of it and when it’ll start doing it again!!



Totally charred!!
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Old Oct 15, 2020 | 06:01 PM
  #29  
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2004 sl500
Im having the exact same issues. First I replaced the service battery with a new one just to rule that out. Then when my new siren arrived i installed it and the problem still occurs. The alarm sounds off while the lights flash. I am at a loss on what to do next or even attempt. Siren code cleared and has not come back on my scanner. what else could it be???
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Old Jun 17, 2021 | 10:00 PM
  #30  
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2005 s500 w220
So disconnected it still will not kill the battery? Mine is going off hopefully I can

Originally Posted by NikleinR6
So the newest issue my car has been having, is that when i lock the doors with the smartkey, about 20 secs later my alarm sounds for no reason, and then the tow away lights begin flashing. At 1st i thought, maybe the rear battery is going, then i thought maybe water was getting into my trunk and shorting the pse pump, and lastly i thought maybe my rear SAM was going bad. Luckily for me, it happens that the siren (mounted beneath the driver's side fender) contains its own 2 batteries, and these go bad. When they go bad, they leak battery acid all over the board, corroding it, and leaving you with these issues : everytime the alarm is activated, the siren will sound soon thereafter. The car thinks its being towed/stolen...

Its easy to fix, just remove left front wheel, the rear part of the inner fender liner, and then reach inside (under the fender) and remove the siren. I decided to remove it with the bracket (3bolts as it seemed the easiest). You can buy a replacement from parts.com for 103.00. I left mine out until i decide if i really want to spend 120.00 shipped on something that is useless. I can always order it, and install it in under 20min if i want to later.

I found many other MB owners have the same problem as i think the siren is the same for the entire mb line of cars (pertinent years).
I have a bunch of pics i thought you guys might wanna see that show the damage.. I sawed the siren in half, just to take a look...


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So if it’s disconnected it will not run or drain the battery? About to take a road trip

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