silvertonesx24

After replacing COMAND with an Andorid Unit (car has Harmon/Kordon MOST system) everything was working fine, finally. Except for one thing.. battery drain. I isolated it to the Audio Gateway (AGW) never shutting down. Assuming that it wasn't shutting down due to the new Android head unit, I removed Fuse 6 for a few days to save the battery and decided to try installing a relay circuit to shut down the AGW when the ignition is off.

And after removing the DVD navigation, and power cable to AGW, I decide to plug everything back in to test the system again before I start splicing wires for the relay. Everything is back to how I had it. And..

Somehow I now have NO SOUND. Fuses are fine, AGW is getting 12V, I replugged back in all cables including the fiber loop on the DVD NAV. Any chance this is just coincidental and my AGW is actually failing? Any way to find out before I go chasing more parts? Anything that needs to be reset? My CD changer doesn't open, but I'm not sure if that's because the Andorid unit or not.

And to anyone considering upgrading your COMAND headunit to aftermarket...either pay someone else to do it or don't do it. Worst DIY job I've ever had on any car.

bobgodd

If you're using one of those RCA to MOST adaptor boxes like this one: https://avinusa.com/most-fiber-optic-amp-interface-for-mercedes-benz-e-class-cls-slk-s-cl.html , then just use the 12V trigger wire, not the 12V constant, as it'll continuously use power even when the car is turned off. It doesn't need 12V constant to function, just a switched 12V source.

Edit: I should have read the whole thing. I'd double check all of your connections, make sure something didn't get crossed when you undid things. Is your MOST adaptor loop seated correctly, maybe put the nav drive back and see if you get sound back. The whole MOST network has to be continous or none of the devices will work.

silvertonesx24

Yes, I put the nav drive back, no breaks in the MOST loop.

My MOST decoder is like this one. I did not connect the canbus wires from the MOST decoder, as when I connected the canbus wires from both the decoder and the android navigation, steering wheel controls did not work. The MOST decoder is connected to the switched 12v (cigarette lighter)

https://www.aliexpress.com/item/4000485211930.html

Everything was working fine (audio, canbus, etc) until I pulled the Fuse 6 on the audio gateway. Now, no sound.

silvertonesx24

Not an AGW problem after all- the MOST decoder must be hooked up to the car's canbus to tell the AGW to both turn on and turn off. I disconnected it because it was interfering with the canbus from the head unit. But turns out that was the problem, and I connected the head unit canbus to a different set of canbus wires.

Basically, if you're going to do this android conversion (good luck), you WILL need a MOST decoder that includes the canbus wires. There are some that do and some that don't. I can only assume the ones that don't will lead to problems.