I recently completed installing a Roadtop CarPlay unit for my 2014 W204 C63. I have NTG 4.7, but I think it also works for most MBZ cars as long as they have the correct COMAND NTG version, either 4.5 or 4.7 which I think was generally 2011-2015 production cars. I got it off Amazon for ~$250USD but you can also get it direct from their site, probably eBay, aliexpress, etc.

I referenced this site along with Reddit, YouTube, etc when working this project and I wanted to attempt to pay it forward by sharing some details and lessons learned. There’s a lot of good documentation out there so I don’t want to write too much, happy to elaborate where needed if people have questions. I think there’s some key points about aux/bluetooth connection that maybe deserve some clarification. Seems like I’ve come across at least a handful of recent posts maybe even with unanswered questions on the topic of Roadtop CarPlay for NTG 4.5/4.7 so seems like there’s still community interest.

from a physical labor standpoint, the worst part of the whole thing is probably stuffing the OEM radio unit back into the housing after you do all the cable/harness routing. It’s a tight squeeze. I could say a lot about this, but I’ll save it unless someone has questions I think I can answer. The second worst part is carefully disconnecting the air conditioning vents, the latch mechanism was a pain for me. I don’t recommend doing this without the proper tools and doing lot of research ahead of time. Plenty of good posts out there with more details but critical items are 1) trim removal tools 2) Mercedes air vent removal tools (qty 2) or 90-degree pick tools 3) assorted Torx bits.

Something that I struggled with was using aux versus Bluetooth for wired or wireless CarPlay for my iPhone, and getting the correct settings/configuration. Note that in my center console I have a USB-A port, and a weird-looking port that I believe is officially called UCI, but may also be referred to as AMI/MMI. It’s a multimedia port. My car came with an adapter that plugs into the UCI port and converts that into either a 3.5mm aux input or iPod-style 32-pin input. I also have Harmon kardon speakers.

AUX —if you are going to use aux mode, I don’t think you need to run an aux cable to your center console to connect to the UCI port. What you need to do is go to the engineering menu in the COMAND settings, I think it’s settings 7.7 about TGW parameters, set UCI to not enabled, AUX to enabled. I have HK speakers so I needed to set my amp to external. You don’t need to have anything connected in your center console, and the 3.5mm aux coming out of the harness that plugs into the Roadtop box can be tucked away. There’s a thread on the GL-class (X166) by user “Jason Stewart” where in his post edit he mentions the aux vs UCI/MMI/AMI issue where you’ll have audio problems if you connect via both the AUX integrated in the Roadtop unit (which was news to me) AND the UCI/AMI/MMI port at the same time. This should enable the aux port built into the Roadtop unit to play audio thru the aux mode you selected in the COMAND audio mode/settings. In the Roadtop unit settings, you need to have “use car’s BT channel” and “use car’s BT phone” both off. If you turn one of them on, the device will reboot and hide the other one. So make sure they’re both off. You may also need to mess with the audio settings in the Roadtop unit. I had to turn my master and music volume up from the default settings in order to hear music without any feedback/noise. I also grounded the AUDIO GND cable to the other black GND cable using a lever nut.

BLUETOOTH — you will need to enable “use car’s BT channel”. I’m honestly not sure if you also need to “use car’s BT phone” in the Roadtop setting. I’m not sure cuz currently I have wireless CarPlay working in aux mode (the method above) without having anything (UCI/AUX) connected in my center console. Then, in COMAND audio settings, select Bluetooth and connect to your phone like normal. You will also need to make sure BT audio is enabled in the advanced engineering settings

general comments —

1) I think the way CarPlay is implemented in the settings is a bit nonintuitive. For me, I have my wifi and Bluetooth enabled. Once I see the CarPlay wifi as an available connection, I go to my Bluetooth settings and find the CarPlay Bluetooth option and connect. It connects briefly, as you might see if you have the black-background homescreen open for the Roadtop unit, and then it disconnects Bluetooth and enables CarPlay via Wi-Fi, in my iPhone settings, I go to CarPlay and the device is called LuTuo, and there I can rearrange my CarPlay apps.

2) originally tried getting this working using Bluetooth (rather than aux) because I was under the impression that aux mode meant I needed to run an aux cable to my center console to the UCI port, but that’s not the case IF 1) you can get your settings correct in the advanced/engineering COMAND settings AND 2) you get the Roadtop unit that has the integrated aux harness/connection, which I believe should be standard as of late 2024, if not earlier. This was not clear to me at all until I got everything including audio working. But when using Bluetooth, I was having some kind of intermittent issue where the music would cut out for fractions of a second as if there was some interference in the Bluetooth audio. Not sure why that was or what the fix is but I’m going to try to figure that out soon. Maybe I only need to have “use car’s BT channel” enabled and keep “use car’s BT phone” off. Idk. If anyone had this issue and solved it, lemme know lol.

3) their customer support via Amazon chat is surprisingly responsive/supportive. They sent me a few docs which I’ll try to attach here which were varying degrees of helpful.

4) I highly recommend using an AI tool/app like Perplexity to troubleshoot bugs as you work through this. It’s similar to chatGPT but it’s more like an advanced search engine that embeds citations within the results it spits back so it can be helpful to find relevant threads, YouTube videos, Reddit posts, etc.

overall, despite lack of clear instructions for the DIY crowd, I highly recommend this product to anyone who wants to modernize their car with CarPlay but retain the OEM look and feel etc. attached to this post are some instructions that the support team on Amazon sent me, which helped a non-zero amount.

hope this helps someone. Let me know if you have any questions. Cheers