Hello, I have tried to install a new CarPlay I bought on ebay https://www.ebay.com/itm/235592171919. Everything seems to work fine except for the audio, I don't get any audio.
With the original installation of course the audio sounds great.

All the cables are connected except for this one that was connected to the old screen


These are the original head unit connections


This is what I have already tried to make the audio work with no luck:
* Enter the original command UI and try to play any radio station
* Connect my phone to the original car bluetooth
* Connect the new CarPlay device to the car bluetooth

I'm not sure how your is connected, but mine had a seperate 1/8" audio out cable.

The new device comes with a audio out cable too, it's optional in case your car needs it. But I can't find where to connect it to

Have you selected "aux" from the audio screen? That is what I have to do on mine.

You need to connect the AUX cable to the MMI port in either the glove box or the center console. You need to use a specific mercedes MMI to 3.5mm stereo female connector then the android screen male 3.5mm cable connects there. You also need to be on AUX option in your command to get the sound working.

The audio cable you connected (red and white) are for something else. I think those are for a different input. Unless you will add something to the unit that you will need to sound rendered you do not need to use those. Look at your installation instructions. If the instruction is garbage youtube will be your best resource.

I did not need to this when I installed my wireless CarPlay unit.

Today I tried selecting the aux option from the audio screen, At first the "aux" option was't there I had to go the engeneering menu and after some tweking I was able to enable it.
But unfortunally still not getting audio

I will buy a MMI to 3.5mm stereo cable, the device comes with an adapter to male stereo that gets connected to the "red and white" cables. I have also located the MMI output in the glovebox.
I think it will be a little difficult to place the cables from the center console to the glovebox, but at least before I will try if it works or not.

Thank you

You still have it wrong. The android screen has a female stereo 3.5mm cable. That is the "output" line that needs to go to the command NOT those red and white RCA cables.

The Android screen does not have an stereo female besides the red and white one


This is the adapter I mentioned, This was my last option, I expected the audio working normally without doing this

You should be able to get audio without doing this. Do they have any support?

Yes, but they suggest things that makes no sense, for example they sent me a picture showing a cable that could fix the issue but the android screen in the picture is not the same as mine, it does not have the same connections and even the power cable is different, so the cable they mentioned does not apply to my case. I'm still talking to them but I have no hope

hmmm.....the back of your android unit is very different than those I have seen. I guess yours came from a different factory in China. If that is the only connectors on the harness then that male 3.5mm stereo jack goes to the MMI port (you need to have the 3.5mm to MMI connector like this....(verify your command version as this image is for the NTG4.0-4.5. I believe the later version is a 3.5mm to USB)

I have an NTG 4.5, so mine is a bit different. The company I purchased from also sells an interface for an NTG 4.0, which is what you have. I don't know if this will help, but here are the directions to connect their interface to an NTG 4.0.