Hi all,

I just finished installing the Road Top Wireless Apple Carplay module in my daughter's 2018 C300 that she recently bought. The car has the NTG5.2 head unit. Everything seemed to go smoothly with the installation and Carplay is working great. But, after the installation as I was testing everything, I noticed that Satellite Radio (SiriusXM) is not working. When I select Satellite Radio from the COMAND menu it says "Device Unavailable." AM & FM radio and all other audio sources are working fine. When I was doing the installation, I did make sure to move the fiber optic cable from the OEM harness to the Road Top harness.

After noticing the problem, I uninstalled the Car Play box and returned everything to the way it was (including moving the fiber optic cables back to the OEM harness). After returning everything back to stock I am still getting the same issue if I select Satellite Radio. As far as I can tell, everything else is working just fine. Since Satellite Radio wasn't working without the CarPlay box, I reinstalled it and my daughter is using it. But, I'd like to figure out what's going on with the Satellite Radio. Unfortunately, I didn't check if Satellite Radio was working before the installation (and my daughter doesn't know). So I don't know if I broke something during the installation, or if it just wasn't working before.

For what it's worth, I can see one of the fiber optic cables light up, but the other cable doesn't light up. I don't know if that means anything. Does anyone have any idea what I might have broken or what to check? Is the Fiber Optic cable the only cable that needs to be connected to the HU for Satellite Radio to work? For reference, I've attached a photo of what the back panel of the head unit looks like.

If anyone has any ideas, I would really appreciate it!!