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I am installing a subwoofer to my 2012 w212 sedan, i have the factory sound system with no subwoofer.
does anybody know where to tap into in the trunk area to get a remote out wire for my amp?
i already tapped into the rear speakers for hi input signal.
How are you getting the signal for the subs? You can use a line output converter, with a remote switch on, to provide both the low voltage audio signal plus the power on signal to the amp.
I am installing a subwoofer to my 2012 w212 sedan, i have the factory sound system with no subwoofer.
does anybody know where to tap into in the trunk area to get a remote out wire for my amp?
i already tapped into the rear speakers for hi input signal.
> REMOTE ON/OFF...
-- You can review the WIS diagram by VIN for any match in your specific main amplifier connections...
or
-- You can try a simple "AUX Accessories" from a SAM fuse mofule
or
-- Use an Amplifier that senses signal.
> MAIN POWER ... GREMLINS FARM...:
The No1 issue is the Amp Power supply and chassis single GND strap.
You'll want to minimize riple noise that will impact chassis modules internal capacitors & networking.
The point here is you can expect high current power to wake up built-in gremlins as in more unstable CAN-B Keyfob.
> VARIABLE VOLTAGE...
Your stock MY'12 runs a smart ALT that provides variable voltage from 14.9 to 12.6Volts.
How many Watts is your new Amp ?
Calculate the difference in Amps-Current between low/high voltage... should be significant!
There is an experimental way to gain fixed voltage by disconnecting ALT-LIN for a 14.15V output under normal use. Not tested under heavy power demands.
A stronger ALT may be needed to supply new power to audio extension.
> STARTUP RIGHT....
Powering the Subwoofer Amp is far from a "Plug'NPlay" project.
Besides the main audio Amp itself fries the stock speaker channels with DC output - Best not to use the stock setup from the get go.
Last edited by CaliBenzDriver; Feb 14, 2026 at 02:27 PM.
I have the same question. The 2013 E200 I have does not come with any audio in the rear parcel shelf, only door speakers. I need to tap the inputs for the rear speaker, preferably on the driver's side. My active subwoofer has auto-sensing for turning on.
I plan to power it off the aux battery in the boot as I always turn of ECO mode immediately I get into the car.
Any ideas on where to find the speaker wire inputs for the rear door speakers and their colours?
I have the same question. The 2013 E200 I have does not come with any audio in the rear parcel shelf, only door speakers. I need to tap the inputs for the rear speaker, preferably on the driver's side. My active subwoofer has auto-sensing for turning on.
I plan to power it off the aux battery in the boot as I always turn of ECO mode immediately I get into the car.
Any ideas on where to find the speaker wire inputs for the rear door speakers and their colours?
Sounds like standard audio system, not Harman Kardon, HK had the sub woofer amp and sub woofer speaker installed.
Pretty crap audio systems.
I replaced all the door speakers with paper cone speakers because the metal cone speakers sound crap.
Sub woofer had burnt out voice coils and I pulled the speaker cone out and I rewound the coils.
Common problem with them
The sub woofer amp is located in the boot on the left hand side (sub amp is separate small box in my car)
The wiring might be there for yours though and you could pick off that.
Problem is, if I remember correctly, the audio system signals are digital, not analogue, so you need to pick off after signal processing which means you need the box
The sound system has an audio filter built in to the sub amp to pass the low frequencies.
Sub woofer system combines the left and right channels, there is only one speaker.
You can get sub woofers that have dual voice coils.
I ran some serious tests of frequency response and audio power levels using test equipment the result of which you will find in my posts
I tried a Fusion PF-SW100D4 to tried to improve it, but came to the conclusion in the end that HK engineers didn't do a good job
See if the wiring is in your car, then maybe you can add the sub amp, and pick off the audio from that to run your sub woofer amp to boost the bass to the sub woofer you have chosen
One subwoofer with two voice coils shown. The other speaker is rear surround sound.
Last edited by Bruce Hubbard; May 3, 2026 at 11:00 PM.
Reason: sub amp wiring added
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Need to find remote out wire w212
