|
Floobydust
Veteran
Date registered: Mar 2014
Location: Massachusetts, USA
Vehicle(s): 1995 E320 Cabrio, 2003 G500, 2000 SL500, 1980 TR8
Posts: 284
| A few factory alarm questions . . .
Yesterday the G decided that I didn't have enough stress in my life and so started randomly sounding the alarm siren and flashing the lights. I did the usual check for open/ajar items and all is well. After I got home, I checked the hood switch with an ohmmeter and it is functioning as expected. It still went off randomly, but only when the alarm was "armed" (e.g. truck closed and locked with remote). To avoid war with the neighbors, I did a siren-ectomy to silence things. This also seems to have stopped the flashing lights as well.
I read that the alarm siren contains its own battery and supposedly it "alarms" to indicate that the internal battery is failing. I can understand that, but I would be surprised if that would also flash the lights as I don't think there is two-way communication between the siren and the alarm control module. Does anyone know?
I don't really care if the alarm works, but I have a concern that the lights will still flash at random times, potentially running down the battery and leaving me stranded. Does anyone know if disconnecting the alarm siren also disables the alarm system?
The EPC says that there is a separate alarm controller (203 820 27 26) although I have read posts that claim the alarm function is integrated into the SAM. Does anyone know where the alarm control module is located on the G? I fear it may be in the dreaded center console area.
It's not fun tracking down intermittent "gremlins" like this because they can eat through a lot of time and money. Does anyone have any other suggestions/experience with a similar situation?
Thanks!
|
|
| |
|
Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| RE: A few factory alarm questions . . .
I too have had a similar issue. Instead, I have been locking the truck by opening the rear driver's side door, then locking the front driver's side door from there. It locks the doors, but doesn't activate the alarm system. |
|
| |
|
djdinaz
Extreme Veteran
Date registered: Jun 2007
Location: Arizona
Vehicle(s): 03 G55
Posts: 439
| Re: A few factory alarm questions . . .
Perhaps it's a bad tow away sensor.. That part you list is for a different G -- look at A2118209126.
Its sensor B33 found in the console between the seats. If you have a WIS, drill into group 80, subgroup 50. There are a number of docs in there for testing actuation, etc.. I think the early 463s use the DCM/microswitches and EIS all tied to the SAMs, along with the tow away circuit. (I'm trying to get a good copy of GF80.20-P-0005GA from ETM printed out, but, it keeps cutting off the sides). |
|
| |
|
Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| RE: A few factory alarm questions . . .
I just remembered something...
When I was last at the dealership, I went through the STAR system with a fine toothed comb. In the alarm system, it showed every one of the sensors that triggered (since last reset) that triggered the alarm system. In my case, there were multiple sensors. I had them all reset, but haven't been back to find which one was setting off the alarm. I forgot about that... |
|
| |
|
Floobydust
Veteran
Date registered: Mar 2014
Location: Massachusetts, USA
Vehicle(s): 1995 E320 Cabrio, 2003 G500, 2000 SL500, 1980 TR8
Posts: 284
| RE: A few factory alarm questions . . .
djdinaz - Thanks for the heads up on the p/n - a little cut and paste error on my part.
So I tossed a c-class siren in the bucket at the local pick-n-pull while getting some parts for the W124 so that I could "dissect" it and gain a little more insight into its operation. It's quite a complicated piece of kit inside - a 250mAH Nimh Hydride backup battery, a charging regulator, audio drive circuity, and most importantly, what looks to be a custom ASIC, indicating to me that the communication between the siren and the alarm module is more complex than a simple high/low signal level. The inside of the JY unit was pretty corroded from the battery out-gassing, so I can see why these things fail with time.
After my little bench session, I decided to reinstall the original siren and sure enough, the alarm goes off by itself within about 5 minutes of being armed. Remove siren, and it seems to be fine. I also checked to see if the alarm is even capable of arming and detecting an open door. etc. and yes, the lights will flash when the alarm is deliberately set off. So the siren does seem to be implicated. I just have a hard time believing it. I am going to "observe" the system for a while with the siren removed just to be sure (I don't really need the alarm function).
|
|
| |
|
AlanMcR
Expert
Date registered: Apr 2006
Location: US, CA, Los Altos
Vehicle(s): G300DT E300DT 230SL
Posts: 3500
| RE: A few factory alarm questions . . .
Floobydust - 8/31/2015 11:15 AM djdinaz - ... It's quite a complicated piece of kit inside - a 250mAH Nimh Hydride backup battery, ... This was designed to fail. The engineer who designed this piece of excrement and anyone who approved of the design, should be fired. Just my humble opinion.
|
|
| |
|
Floobydust
Veteran
Date registered: Mar 2014
Location: Massachusetts, USA
Vehicle(s): 1995 E320 Cabrio, 2003 G500, 2000 SL500, 1980 TR8
Posts: 284
| RE: A few factory alarm questions . . .
Another update (mostly for future thread searchers) - I mixed and matched the best parts from the junkyard sirens to create a working "frankensiren" which I installed in the G. It now sounds when it should and remains silent when it should, providing more positive proof that the problem was a failed siren. At some point I will order a new new, but at least the alarm is working in the mean time.
Edited by Floobydust 9/5/2015 11:30 AM
|
|
| |
|
Braingears
Expert
Date registered: Apr 2006
Location: St Petersburg, FL
Vehicle(s): G320 & ML320
Posts: 1450
| RE: A few factory alarm questions . . .
I'm going to have to check mine now. |
|
| |
|
NHDave
Extreme Veteran
Date registered: Dec 2013
Location: Seacoast NH.
Vehicle(s): 2004 AMG
Posts: 464
| RE: A few factory alarm questions . . .
Thank you Floobydust for taking the time to narrow down the cause behind the "Random Alarm activation".. In my situation..the alarm sounded while driving. No dash warning, no flashers or dome light activation. I thought the sound was coming from the person behind me, until he made a left turn. I pulled over, remove the FOB, still sounding, unlocked with FOB, stopped sounding. Drove home without further incident, parked in the driveway and feared for the neighbors peace all that night. Online I found someone who figured the siren's batteries to be the culprit, as did Floobydust. I removed the siren and brought it to the bandsaw. Here's a couple photos that say guilty!!!!
 (IMG_0847.JPG)
 (IMG_0848.JPG)
Attachments
----------------
 IMG_0847.JPG (72KB - 1 downloads)
IMG_0848.JPG (109KB - 1 downloads)
|
|
| |
|
Floobydust
Veteran
Date registered: Mar 2014
Location: Massachusetts, USA
Vehicle(s): 1995 E320 Cabrio, 2003 G500, 2000 SL500, 1980 TR8
Posts: 284
| RE: A few factory alarm questions . . .
Yes, given the design, I'm surprised that these units last as long as the do. By way of note, my "frankensiren" has been going strong for two years now, although I'm sure that the mere mention of it in this post will ensure that it fails soon. |
|
| |
|
GwagenLover
Extreme Veteran
Date registered: Apr 2006
Location: Winston Salem, NC USA 27104
Vehicle(s): 2016 G550 & 2016 GLE350
Posts: 473
| Re: A few factory alarm questions . . .
So, I'm wondering if other Mbenz vehicles have this same alarm siren in them.
I hope not.
While on this subject, where was the siren physically located in your Gwagen? |
|
| |
|
NHDave
Extreme Veteran
Date registered: Dec 2013
Location: Seacoast NH.
Vehicle(s): 2004 AMG
Posts: 464
| Re: A few factory alarm questions . . .
GwagenLover - 6/15/2017 7:58 AM So, I'm wondering if other Mbenz vehicles have this same alarm siren in them. I hope not. While on this subject, where was the siren physically located in your Gwagen? Tucked way up, right behind the drivers/left side headlight. Not easy to see, looked three times..convinced it was located somewhere else. |
|
| |
|
ychung
Veteran
Date registered: Aug 2015
Location: SO CAL
Vehicle(s): 2004 G500, 2014 ML350, 2008 S550
Posts: 196
| RE: A few factory alarm questions . . .
I had an issue with alarm too, which I didn't even know it wasn't working.
I found out only because it ended up blowing the fuse that was also connected to the door lock which resulted in key fob unable to lock and unlock the door.
Alarm didn't go off when I unlocked the door with metal key, and that's how I found the issue and solved it with replacing the alarm. |
|
| |
|
imjustdave
Regular
Date registered: Feb 2012
Location: Bonney Lake Washington USA
Vehicle(s): 2004 G500, 2014 Audi Q7 TDI, 2006 Ram 3500.
Posts: 77
| Re: A few factory alarm questions . . .
Anyone feel that these batteries could be replaced before they cause issues.
|
|
| |
|
AlanMcR
Expert
Date registered: Apr 2006
Location: US, CA, Los Altos
Vehicle(s): G300DT E300DT 230SL
Posts: 3500
| Re: A few factory alarm questions . . .
I would suggest removing the alarm, if possible. I have seen these same batteries used in older computer systems, they died horrible deaths there too. Usually eating up the nearby circuit boards. If you do replace, you might want to think about using standard NIMH AA batteries in an external pack.
|
|
| |
|
Boss
Member
Date registered: Apr 2017
Location: Washington DC
Vehicle(s): G500
Posts: 13
| Re: A few factory alarm questions . . .
I just had the same issue. I bought a new alarm siren and replaced the old one, works like a charm. Amazon has it for about 150
MERCEDES-BENZ 2198203226 GENUINE OEM SIREN |
|
| |
