Acoustic lock stopped working after horn change
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 46
Likes: 2
W212 E-class
Acoustic lock stopped working after horn change
As the title says. My horn broke and I replaced it with another horn, but then the acoustic lock, when locking my car, the horn stopped giving feedback. I thought the horn was the problem since it was used, but I just bought a new oem s class coupe horn and the acoustic lock still didn't work. The feature is activated inside the car, so where is the problem? I have w212 2016.
Banned
Joined: Oct 2005
Posts: 4,957
Likes: 1,640
I have never heard of a horn going bad on these cars. Maybe go back into your settings and deactivate your acoustic locking verification signal and then back out of the settings and then reenter and activate it again. If that does nothing then the horn may need to be coded. Once again, I have not seen this issue before and cannot imagine the horn needs to be coded, but who knows.
MBWorld Fanatic!
Joined: Apr 2006
Posts: 4,694
Likes: 1,829
From: Dallas-Ft.Worth,TX
2016 E350 Sport
As noted, the lock horn is not automatic. You have to enable it in the settings menu. If you replaced the horn (for some strange reason as KEY08 says) I am sure the default is disabled, as the car was delivered. I enabled mine after purchase, but recently disabled it.
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 46
Likes: 2
W212 E-class
I have never heard of a horn going bad on these cars. Maybe go back into your settings and deactivate your acoustic locking verification signal and then back out of the settings and then reenter and activate it again. If that does nothing then the horn may need to be coded. Once again, I have not seen this issue before and cannot imagine the horn needs to be coded, but who knows.
The horn went bad due to heavy rain. It was very rainy and there were many ponds of water. The Low frequency horn went out because its hole was pointed towards the bumper so water could easily enter. The High frequency horn on the other hand was at a better position so it was more water resistant. Sorry I forgot to mention, but the acoustic lock is already enabled in the car. I did try to deactivate then activate it but no luck. I also tried to deactivate, drive the car for a while, turn it off, then I activated once again and drove for several miles again and then I locked it to test the acoustic lock but still no luck. I don't know what to do and even my mechanic has no idea.
Banned
Joined: Oct 2005
Posts: 4,957
Likes: 1,640
Maybe disconnect the battery for 30 min. Not sure what else you can do. I'm not sure if the front SAM controls the lock function sequence or not. It doesn't seem that a failed horn would remove this function from your car. If the replacement horns all honk then something is not communicating with something. I know that was profound, right? One other thing, the SAM is very susceptible to water damage, which makes me nervous with your episodes and water gushing into your car.
Last edited by RA72825; Jan 2, 2020 at 02:48 PM.
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
Do they both work when you press horn on steering wheel?
With latest SCN-frenzy ideas, I wonder if the horns might have module that require coding, or pairing.
With latest SCN-frenzy ideas, I wonder if the horns might have module that require coding, or pairing.
Trending Topics
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 46
Likes: 2
W212 E-class
BTW I forgot to mention, My mechanic was changing my brake pads at the same time he was changing my horns. I don't know if they are related or no but I thought it's worth mentioning. Also, I mentioned this before but I want to stress it, after the brake job and the service in general, I reinstalled my old horns (one was working and the other not) and the acoustic lock was also not working! So is it related? I will try disconnected the fuses as suggested by konigstiger
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 46
Likes: 2
W212 E-class
P.S: I pulled out the relay and fuse while the car was off, is that how am supposed to do it?
Last edited by Saud Aljeziri; Jan 2, 2020 at 05:25 PM.
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 46
Likes: 2
W212 E-class
Last edited by Saud Aljeziri; Jan 3, 2020 at 12:38 AM.
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 46
Likes: 2
W212 E-class
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
1 disconnect is all you need and no need to disconnect aux battery.
I was disconnecting the car for vacations who were planned for 3 months, so I pulled the battery on garage floor and hooked up maintainer on it.
I was disconnecting the car for vacations who were planned for 3 months, so I pulled the battery on garage floor and hooked up maintainer on it.
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 46
Likes: 2
W212 E-class
Ok so I disconnected the battery for about 15 minutes and I turned on the headlight to completely dissipate any charge in the system. The horn works fine along with everything else but the acoustic lock still doesnt work...
