[Acid307]

Hi, I have a 335i e93 and unfortunately the stereo has stopped working, there is no sound from the unit including the bmw gong sounds etc. I have looked through the forums and seen a few videos but these are all aimed at replacing the amp etc or putting the optical loop in to remedy the issue, unfortunately being the base model I don’t have an amp to replace? Could anyone point me in the direction of what I should be thinking of doing to fix the problem? I’ve fitted a few aftermarket stereos, subs and amps over the years (Essex boy) but even knowing where to start with this has stumped me. Any help really appreciated .

[ctuna]

It seems pretty straight forward that if you only have a Head Unit that is the source
of the sound the Head unit is the problem.
If you bought this car from someone else then maybe not so straight foward because
you may not no what they did to it.

Please read these there is also a base system upgrade thread gide that covers all the bases newer equipment may be used.
Putting and aftermarket head unit in has some issues with breaking the Most bus connection.

BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/attach...1&d=1209780865
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/showthread.php?t=641323
http://www.e90post.com/forums/attach...4&d=1278871872
http://www.e90post.com/forums/showthread.php?t=343673
https://www.bimmerfest.com/threads/e...n-752.1275694/

base system wiring pre/post 3/09
https://www.google.com/url?sa=t&rct=...tDpLJPcGkw_ui_
Base System Guide
http://www.e90post.com/forums/attach...5&d=1493273253

[Acid307]

Thanks for that, I will have a good look through. One question though, where are would the fibre optic from the head unit run too ? I was hoping to try using a return to loop the signal back to test what component of the fibre optic chain is faulty so I can diagnose what’s causing the issue ?

[ctuna]

If you truly have the base system there are analog connections between the
speakers and head unit as seen in the diagrams the Most system has nothing
to do with sound in the Base and Hi Fi system.

Read the links.

Stereo or base system no amp . No option number
Hi Fi system small amp analog connections between amp and head unit. Option 676
Top Hi Fi aka Logic 7 fiber optic connections via the Most Bus to the amp OPtion 677 or 688 depending on model year . 688 lacks rear tweeters.

Mdecoder.com will list you options via vin number.

READ THE LINKS

[sam9116]

You don't need to have an amp to mess up your fiber optic loop, if your car have any other options that involves sound (Hands free calling, voice recognition, bmw assist(sos button), usb audio, satellite radio, cd changer, they can all be potential suspects

Find the location of all the potential module you might have, unplug the most cable from it (green), and insert a bypass, and you can dwindle down what might be failing. I have not seen a single radio that fails by itself in the past few years I worked with them

[Acid307]

Originally Posted by sam9116

You don't need to have an amp to mess up your fiber optic loop, if your car have any other options that involves sound (Hands free calling, voice recognition, bmw assist(sos button), usb audio, satellite radio, cd changer, they can all be potential suspects

Find the location of all the potential module you might have, unplug the most cable from it (green), and insert a bypass, and you can dwindle down what might be failing. I have not seen a single radio that fails by itself in the past few years I worked with them

This is what I am planning to do I’m just struggling to find the location of the module I should be starting with. I’ve seen possibly the combox as the car does have Bluetooth?

[sam9116]

Combox is only available if your car is 2011 or newer, it's most likely a tcu/mulf setup, although it will be at the same rough location