X164 2009 GL450 no audio
Problem: No audio at all. AM/FM radio says device unavailable. Sat radio say "Please wait"
What I've done so far: I've bypassed the Sat/HD radio unit under the second row seat with an optic cable loop. No change.
Before getting the bypass, I thought it is the amplifier as there was water in the trunk (liftgate issue, another story). Got to the amp under the driver seat and it was in decent shape. optic cable was blinking too. Didn't have the bypass loop use at that time.
I've done COMMAND soft resetting. Checked all fuses and pulled them out for audio component to reset them etc...
Clue less at this point. Shouldn't it be the Sat/HD radio unit as it says device unavailable? Could it be the audio gateway that causes all this?
I read somewhere that SOS system is out of this loop and should make a sound if used. I tried the SOS button on the ceiling and nothing happens!
Backup camera shows blank screen. No guiding lines either. I think it is unrelated. Checked the connector in the tailgate and all good.
Is there a diagram of what else is in the optic loop?
Thank you in advance.


