Hey all hope someone can help for a simple question. Has to be for a 2020 since the colors of the wiring has changed. I have looked all over and cant find it. If I cannot get this I will have to remove the carpeted side walls in the trunk to see if I can see the wire colors that way. If anyone has this or instructions to remove the side carpeting I would be thankful.

I got my new 2020 and want to add a subwoofer and amp. Some great posts on an other site I pasted. Seems easy to do. Only issue is the wiring colors changed from the older posts I read. I guess the 2020 used different colors.

If anyone has this info it would greatly be appreciated.


1) The subwoofer is in the drivers fenderwell (huh?). You have to pull the wheel, and both liners. Not going to happen. Factory amp, nope too much. My goal - what’s the easiest, cleanest install with minimal impact and reversabable.

2) According to the wire harness, speaker wires (positive / negitive) are twisted together. Lot easier to find.

3) Wire harness mentioned above runs through the spare tire department. So no need to remove panels or mess with fender liners. In fact, I didn’t pull one single panel.

Super easy install. I used the bolt stubs within the battery compartment to fasten my amp down. It was a near perfect fit. No screws, holes, etc. Just a few metric nuts and washers.

Battery (+) straight to positive manifold (see pics) with fuse

Battery (-) to body using existing bolt stub (metric)

Remote (switched +) used a mini fuse tap, plugged into second (10 amp) fuse labeled stereo amp. The aftermarket amp only needs .5 amps to switch on

Signal - see pics for wire color. Used taps too, so that I can remove with minimal evidence. Only picked on channel, it’s subs.

Installed Lc2i to clean up the signal. Curious if needed, my Mercedes needed it really bad.

What’s great, I can control through the subwoofer settings on touch screen (like a remote knob).

See pics of install (before wire loop and finally clean up)

I know this isn’t everyone’s cups of tea... Cheers!

Wires for the factory subwoofer in the 325W system are indeed in the same harness and in twisted pairs, but for whatever reason are colored differently. They are as follows:

Sub 1 + : Red
Sub 1 - : Yellow
Sub 2 + : Red
Sub 2 - : Grey