Hey all I've got a weird issue with a 2012 R56 LCI MCS that I picked up from someone who got a too big repair quote from the BMW dealership. I have no front audio from my speakers in the doors both left and right as well as the tweeters in the A pillars. I also have the H & K system with boost radio no navi screen type setup. The wiring in both doors is fine from the connector at the speakers as well as the door bulkhead connectors, checked with a multimeter. The speakers are also fine with no tears to the membrane or continuity problems in the wiring of the speakers itself, as far as I can tell anyway. They are also stock speakers with the BMW logo and appropriate install date sticker. The rear speakers in the side panels in the back seats work great with no issue. The standard chimes and warnings for things like headlights on or door open also do not play or notify at all not even through the rear speakers.

Short of taking apart the dash to check the wiring to the back of the radio is their any where else I could check to see why I'd have sound in the rear but nothing up front.
Changing EQ settings doesn't have the desired effect as it only will change it from left to right bias.

Thanks for your suggestions if any come up!

 

The obvious: Fader set at only rear?
Do the front channel signals arrive at the X9331 connector? If so, possibly a fried factory amp (there are plenty reports of them failing).

Note: I do not have an HK system so I can't say whether chimes, warnings, etc. are suppossed to be played in your case via both front and rear channels or only the front. However: PDC sounds are emitted only via the rear channels. If your car has PDC and you're not getting them via the rear speakers, then your head unit is possibly (also?) affected.

 

The fader control only works from left to right. Working it from left to right does change it but only from the rear speakers. :( Where is the X9331 Connector? I've seen it in the wiring diagrams but they don't give it location... That I can see.
I also don't have an AMP in the general location it should be. The trim panel also suggests that their isn't one "supposed" to be their. Taking it off I found no provisions for a cable connection of any kind. Which is weird. The same goes for the other panel access on the right, studs for mounting something but even the threads are clean and unmarred and no cable connections or provisions for one all along the run.

Left rear area where AMP should be.

 

X9331 lower left foot well area. Looks like I'll check that out when I get off.

 

My R56 has the navigation display and has separate "bars" for balance and fader (both being set by moving the curser from left to right). I'm not sure how setting the fader works on cars without the navigation display. Do you mean, there is/was a fader control but it is a. inactive, b. irresponsive, c. nonexistent, d. else?

This is correct (trim for "no amp", no wires/connectors but provisions for the HK/Hifi amplifier mounting bracket) for cars with the base sound system. "Clean threads" also indicates that there hasn't been someone in there who's removed the amplifier. Btw: cars without satellite (US) or digital (EU) radio have no equipment on the right hand side of the trunk.

Regarding the X9331 connector, please note:
- there are power wires running through it so make sure to look up the pin diagram (search NAM for that) and avoid shorting those with ground at all cost!
- there is DC voltage on the sound wires, even without sound, as soon as the head unit is activated (e.g. when unlocking the doors). Using a simple multimeter will only provide limited feedback. If possible, I'd use a short peace of double wire to connect each pair or speaker pin outs to a spare speaker to check whether there is sound. If you have no spare speaker: the top speaker in the passenger side door can be removed easily with minimal effort.
- no warning chimes, etc. at all points to a defective head unit as possible cause. Unfortunately, I no longer have speakers connected to rear channel output so I can't test on mine whether they are emitted via both front and back or only front channels.

 

So I gave that connector harness a probe. It appears the radio headunit is not outputting any power to the speakers in the front. I have continuity at the connector in both directions, to the speakers and to the headinit itself. I can read voltage going across the wires to the rear speakers but absolutely nothing to the fronts :(. It doesn't seem like too much of an effort at this point to get to the radio but the cost of a new(yikes)/referb/used one is a little high and stops me. I can't find much about getting it repaired or renewed since the issue doesn't seem common enough to warrant anyone looking into it on their own. I wonder where to go from here. :,(