OK, now I've done it....I think!
Newbie
Joined: Mar 2025
Posts: 1
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Hi everyone. I just joined to add some knowledge to this thread, and I'll separately post on an install of a backup camera/Airplay kit (from emerald integrations) that I recently installed.
On this topic, I had the same issue as well, on a 2014 SLK while I was doing my backup camera combo install. I may've made a mistake and changed Aux to ON prematurely, as I did not yet have the AUX cable plugged in. Sound was fine on the head unit when in the factory audio sources, like FM, then I shut it down and go to sleep and the next day all regular audio from the head unit is gone. Also, I run the circuit test and it says Loudspeaker NG. Ugh.
In poking around, I found some sites that all copy and paste the same info having to do similar issues, and they have a sequence of switching the Audio source (7.5 TGW Parameters, option (2). It's pretty clear they are copying and pasting the same info, as they all have the same typo. In any event, a few nights ago I did the following, and my sound is back and has stayed back. Specifically, and based on those posts, it's pretty clear that some cars have an issue switching the audio source when you make a different change, which in my case was either when I turned MOST off then on, or when I changed the AUX to on, but whichever it was, the Audio source then changes but it does not go into effect after the car goes to sleep. So, when I thought I had everything working, the change hadn't gone into effect -- I shut the car down for the night, but only the next morning was the failure apparent.
To fix this, I went into engineering mode, go to 7. HW settings, choose 7.5 TGW Parameter, (2) Audio source, and set it to external amplifier. Then, without exiting Engineering mode at all or making any other change, I shut off the car, locked it, and let it go to sleep mode (which evidently it does if it's left locked for at least 10 minutes.) The sites I found about this source are not at all clear as to when internal amplifier versus external amplifier is appropriate, but all I know is it made the sound come back, and it's been back for days. I have no idea if my car is optioned in some way having to do with the amplifier, but I'm pretty confident there's no aftermarket amplifier, so this made it work BEFORE I completed the new backup system audio portion.
In fact, as I completed my install, I later connected the system to the aux cable in the console (that connects to the AMI port), and in playing with the Engineering mode once again it switched back to internal amp, so I repeated the steps above and again it fixed it.
Hope this helps others.
Cheers.
On this topic, I had the same issue as well, on a 2014 SLK while I was doing my backup camera combo install. I may've made a mistake and changed Aux to ON prematurely, as I did not yet have the AUX cable plugged in. Sound was fine on the head unit when in the factory audio sources, like FM, then I shut it down and go to sleep and the next day all regular audio from the head unit is gone. Also, I run the circuit test and it says Loudspeaker NG. Ugh.
In poking around, I found some sites that all copy and paste the same info having to do similar issues, and they have a sequence of switching the Audio source (7.5 TGW Parameters, option (2). It's pretty clear they are copying and pasting the same info, as they all have the same typo. In any event, a few nights ago I did the following, and my sound is back and has stayed back. Specifically, and based on those posts, it's pretty clear that some cars have an issue switching the audio source when you make a different change, which in my case was either when I turned MOST off then on, or when I changed the AUX to on, but whichever it was, the Audio source then changes but it does not go into effect after the car goes to sleep. So, when I thought I had everything working, the change hadn't gone into effect -- I shut the car down for the night, but only the next morning was the failure apparent.
To fix this, I went into engineering mode, go to 7. HW settings, choose 7.5 TGW Parameter, (2) Audio source, and set it to external amplifier. Then, without exiting Engineering mode at all or making any other change, I shut off the car, locked it, and let it go to sleep mode (which evidently it does if it's left locked for at least 10 minutes.) The sites I found about this source are not at all clear as to when internal amplifier versus external amplifier is appropriate, but all I know is it made the sound come back, and it's been back for days. I have no idea if my car is optioned in some way having to do with the amplifier, but I'm pretty confident there's no aftermarket amplifier, so this made it work BEFORE I completed the new backup system audio portion.
In fact, as I completed my install, I later connected the system to the aux cable in the console (that connects to the AMI port), and in playing with the Engineering mode once again it switched back to internal amp, so I repeated the steps above and again it fixed it.
Hope this helps others.
Cheers.
