Rear Deck Subwoofer Amplifier
 

This refers to operation of that amp, it's the small gizmo hanging from the rear deck with what look like heat sinks surrounding a small fan assembly.

Is that fan supposed to be working at all times when the radio/cd is on?
Mine is not working (fan is not locked up) wondering if it's a logic-controlled cooling fan controlled when the heat builds to a certain temperature? Seems that the fan would run as soon as the radio is turned on.So I'm thinking that lack of bass may be to the amp itself not working.

I checked rear trunk fuse panel fuses 67 and 69 that are tagged as "sound system" for continuity, the fuses were fine.
Fuse 67 is 40a labeled as "sound system amplifier control unit".
Fuse 69 is 25a labeled as "rear bass speaker amplifier", so it's this circuit I got interested in.

I have not yet pulled the connector at the sub amp to verify actual power to the unit, just wanted to ask someone about the fan operation as a first quick check. I also need to go back and verify power to the fuse 69 itself.

Most fans on amps are regulated by thermal sensors. Run the system at moderate/high volumes for a while and check it again.

Will do, I wondered about that but couldn't find anything on the actual amp operation.
If anyone can run a quick check by simply turning the radio on and taking a peek to see if the fan is or isn't initially running I would appreciate it. Just getting a baseline. Thank you.

Well I headed out for some errands, had the radio on at medium loud, checked when I got back and that little fan was still off. I can hear bass but it seems to be thru the mid/low range of the speakers, not that distinct "sub" sound. Maybe I'm expecting too much, dunno.

I'll check mine today. You should definitely hear that thing going, if you stick your head in the trunk while it's working all you should hear is low frequency sound. I have an E46 with HK sound and it's got nothing on the W212, so the bass is definitely there (both have good bass actually). I keep it at +4 and it's plenty enough, at least IMO. Yours might be misbehaving.

Thanks very much. I can hear some general bass but it really sounds more like what's coming out if the speakers, not the deep lows. That fan has never come on. I'll pull the connector to at least verify power to that amp.
What really gets me is my own oversight if indeed a failed amp that I didn't notice while the car was still covered under ELW!

Until real time feedback f69 is applicable. Subwoofer replacement part # is 2128202302, speaker amp 2118705189 if need be.

Wow, thank you! I was just checking out the wiring in the WIS as well to verify power at the amp plug. Your info is extremely useful, I appreciate it.

The stock sub is worthless, what little sound it puts out is terribly distorted. Remember MB makes cars for old rich people that like talk radio and Opera. I disconnected it when I installed a real sub in the trunk for about $250, worlds of difference. Search for the install thread. With a real subwoofer, the rest of the factory system is pretty good actually.

I verified that the sub is actually working. After some time with the radio on, the heat sinks on that amp are warm and I can get a slight poof of air out of the fan opening. Never have seen the fan working though.
I did also go back and check the sound settings. I agree, the performance overall is pretty dismal, anything further will be an additional of external amp/sub.
Thanks for the thread info, I'll read through it.

I have been pleased with the subtle improvement in bass response from the JL Audio Powered Subwoofer I installed. It is almost invisible in the trunk and the amount of fill is sufficient without being overwhelming.

https://cimg1.ibsrv.net/gimg/www.mbw...948b6f3849.jpg

Honestly my Rockford 10" powered sub only has the gain about 1/3 up to balance with the rest of the system, but it has plenty more if you really want it. It fits nicely against the back seat, I don't think it takes up any more room than the JL picture above, and fairly inexpensive for a self contained quality unit with amp inside.

Deleted duplicate.

My rear speakers just started making a "popping noise". I am trying to trouble shoot this issue. I am realizing there are multiple amps in my radio system.

Is there a way to test? Also, the manual that you provided PDf for... is there a place i can download ?

MBUSA but you can search ebay: “wis epc Mercedes” I’m sure members will post their preferred vendor.