B250 2013 W246 No sound from H/K speakers
My daughter has been playing music in the car via blue tooth using media player for the past 3 years with problem. But when her phone rang she would have to talk on the phone manually. My wife noticed this and changed the settings in the head unit to phone setup so she could play music and talk on the phone using the car system. Tested it and worked fine for music and phone.
Next morning my daughter, could not get any sound from the speakers on any function, not even am/fm radio. My wife set it back to media, reset system, I looked on line and found out , that to reset the system properly you need to find the fuse to the audio system, remove them for 3 minutes. Didn't work. I unplugged the fiber optic cable from the amp and noticed 1 of the connectors on the amp will stay illuminated red for approx 5 seconds and then flash, but the connectors in the cable connector do not light up at all.
Does anyone have any idea what the problem could be or does anyone know where I could find a fault finding procedure or even a wiring diagram. Any help would be much appreciated.




I've been watching people on the computer testing components in the optical loop, they are using an optical plug in bypass loop to isolate each component e.g. telephone, sat nav and multimedia. I do realize I can not bypass the head unit and the amp. But if you know how to locate the other components that would be really helpful.
Thanks for your help
Dave




Sorry just noticed the #2 at top right. But can't get any sound when I hold the ON button in for a couple of minutes and yes I have red light at the cable end during start up.
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Last edited by jessbclass; Feb 16, 2025 at 07:00 PM.
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