W221 amplifier replacment
Last edited by argon3030; Feb 16, 2023 at 01:44 PM.
After a TON of research, I decided to take a look at midatlanticmercedes as suggested by argon3030. The Harman Becker Amplifier is now on sale for $461! Though I didn't buy it directly from them, I did contact a friend who works for a MB dealership to confirm the part number. His dealership had the part in stock at a similar price!
The part number is 221-870-77-89-80 "Amplifier - Mercedes Benz" or "Remanufactured Amplifier 7021 For W221". I can confirm it was an exact plug and play match for the Model 7021 amp. It brought the COMAND system from visual navigation only to full AM/FM, CD, MP3, Voice Command, phone, etc.
There is an additional core charge, but all in for a part with a 1 year manufacturer warranty, I feel it's a great value.
Look online. Check with your local dealerships. Now may be a great time to buy a new amp!
Last edited by AlohaBenz007; Dec 27, 2023 at 01:00 AM. Reason: typo
I think he went on to say its a used casing - with entire new internals
The Best of Mercedes & AMG
after show your post i was very curious and I swapped my W221 amplifier with Genesis. It's worked but i have one problem with volume SCROL button. I was not able to control the volume strate, every time I had to change the volume and then press mute button then unmute.
P.s. The Mute trick doesn't work.
AJ
Last edited by WhiteEagleUK; Feb 17, 2025 at 09:07 AM.

I think he went on to say its a used casing - with entire new internals
This seems a sensible solution... certainly miles better than a USED unit that at this point in time is minimum 11 years old, some 18 years old, which are at between $350 and $1,100 on EBAY....compared to new internals for $620.
Last edited by DunninLA; Feb 18, 2025 at 06:30 AM.
we are still after a guinea pig to try programming the Hyundai amp with Merc software that operates minus its correctly functioning vol control - its clearly almost the same unit but can be bought for far less




This seems a sensible solution... certainly miles better than a USED unit that at this point in time is minimum 11 years old, some 18 years old, which are at between $350 and $1,100 on EBAY....compared to new internals for $620.

2 questions:
1) I did check to see that the amplifier fan does not move. Is there any other way to make sure it is the amp that needs replacing and not some other module in the fiber ring?
2) Several dealerships and parts suppliers have this amp in stock. They all seem to have a 20% return charge, which I am fine with, but more importantly, they all seem to have the same language about "Electrical Parts are not returnable." Has anyone ever ordered one of these amps, then found out it wasn't the amp after all, but another module, and tried to return it for a refund -20%?
Last edited by DunninLA; Feb 19, 2025 at 11:53 PM.
The sirius module is a stand-alone unit it has NOTHING to do with sound creation from any other audio source - if it dies it takes down the fibre loop and all things stop due to the break
On FM or AM radio (the Tuner that is also built inside the Amplifier for ALL audio) do you hear anything - if 100% normal the AMP is NOT the issue
The fan is a joke and that will help kill the Amp

On FM or AM radio (the Tuner that is also built inside the Amplifier for ALL audio) do you hear anything - if 100% normal the AMP is NOT the issue
The fan is a joke and that will help kill the Amp
I get no sound from Disc b/c though I am able to load a disc, and the comand says it is reading Gracenote information, it stops there and nothing plays... so no sound from disc.
I get no sound from AUX, which is the last input in used (it has a dot next to the word AUX under Sound options) b/c the word AUX is greyed out... and when I plug my iphone into the AUX receptor as usual, there is no recognition, so no sound.
So bottom line, I get no sound from Radio, Disc, or AUX.

I used a fiber optic loop a year ago and dtermined that my audio except for FM radio returned to normal with the loop inserted in place of the Sirius module. This time, when I insert the fiber optic loop in place of the Sirius, the Disc player, and the AUX, along with the FM, continue to not work at all.
So that made me conclude the amp is the problem. Or the amp AND the Sirius.
Does any have a step by step set of procedures that I can follow to determine with certainty that the amp is not working? I mean instructions that a 10 year old could follow

Last edited by DunninLA; Feb 25, 2025 at 02:17 PM.

The guy couldn't find anything, but get this, hired another guy to come see if the amp works, and that guy said the amp is fine. The stereo shop guy told me the fiber optic loop is intact... he shined light down somehow and determined the problem isn't in the loop.
So I'm back to square one.

ANYONE pretending they are a decent Merc workshop will have one - and if they are any good, should be happy to stand there as you spend 3 minutes plugging it so he can laugh coz merc have been building cars like this for 20 years -
If I read right I should be able to change the volume by adjusting, then mute unmute
and nobody has the FM radio working with the Hyundai amp correct?






