[335i_GP]

I've had my 08 335i for about a month now and have not had any audio volume since I have owned it. The guy I bought it from said it stopped a few weeks prior. Here are the symptoms and what I have checked.
-Head unit works fine, can select stations etc.. just no volume. When I turn the knob.. nothing comes up confirming the volume raising on the screen.
-No door noises/ seat belt/ etc
-I checked all the radio related fuses in the fuse box, and all are good.
-I pulled the amp (Logic 7 HI-FI), took it apart and found some corrosion on some of the board. Thought sweet, I figured it out.
-Ordered the Fiberoptic Jumper from ECS and figured I would just bypass the amp for now and deal with that later.. just wanted some sound.
-The jumper came in.. plugged it in.. and still nothing..
-Was reading about jumping the "TCU".. so I pulled the cover out of my trunk.. and there is no TCU, and whatever goes next to that. All the wiring is laying there.. but the modules are not there. Would this be my problem?

I've done a ton of searching but kind of hit a wall. Anybody have any direction to go?

[ctuna]

http://www.bmwgm5.com/Logic7_6941681.htm

http://www.bmwlogicseven.com/?p=3837

From the above link which has more info
"This amplifier has a diagnostic LED, which will show lots of things you most likely don't know about. Here you can see where it is located. So look at that LED, turn on the radio and look at it:"

Use a BMW Vin checker search to find out what your car came with. If it came with Bluetooth phone or SOS maybe the module has been hijacked. There should be light coming out of one side of the Fiberoptic Connection at the TCU/MULF
location if it was hooked up. I would try the Most jumper there first .

Can you pair a phone ?
http://www.e90post.com/forums/attach...2&d=1260829447

[335i_GP]

Thanks for the info! That's actually the video I followed for the bypass attempt. I just ran out at lunch to check the diagnostic LED from the non connector side of the amp. All I see is a red light, No yellow. When I get home, I will check for power to the amp as suggested in the link above. I do see the red led coming through the fiber optic connector so I believe I should be ok there.. The weird this is, should I be able to jump that connector if the amp was bad and get some sound to the front speakers? If I jump the Fiber Optic Connector, I still have nothing.

[ctuna]

All sound comes through the amp in the case of Logic 7 systems
alarms will be dead if the amp is dead. If you have SOS you should have
a SOS error on the INstrument cluster. The guy in the video suggests if you put the
jumper in at the amp Most Bus connection and the SOS error goes
away you have verified that amp is bad. (or the fuse for the amp is blown)
This is dependent on the rest of the devices on the Most bus
being good.

[335i_GP]

I do not have an SOS Error. My car is not equipped with navigation or anything like that. It has to be an amp issue. unfortunately the night got away from me last night so I never got around to testing anything else. First think I will check is the power coming into the amp, and if that's verified good.. I'm willing to bed the amp is toast. However, still confused because if the amp is bad.. shouldn't jumping the fiber optic connection to the amp let the front speakers work?

[ctuna]

The amp powers all speakers in the car with a Logic 7 system.(that means no sound without a working amp , of any kind)

In the 06 Hi Fi equipped car there was a separate speaker for the
alarms.

In 5 series cars some of the amp channels came for the head unit (until around 2010 I read)
but not in 3 series cars. at least in e9x's

Logic 7
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.google.fr/url?sa=t&rct=j&...slMu2A&cad=rjt
https://www.bmwgm5.com/Logic7_E90_91_92_93.htm
http://www.e90post.com/forums/attach...1&d=1209780605
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.bmwmotorsports.org/pdf/e7...%20Systems.pdf
http://www.e90post.com/forums/showthread.php?t=343673
http://www.e90post.com/forums/showthread.php?t=138949
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.e90post.com/forums/showthread.php?t=641323
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...4&d=1278871872

To be sure what your car came with do a VIN check
with one of the free online BMW vin checkers.

[335i_GP]

Quick update, its has been narrowed down to a definite amp issue. I took the amp apart, and cleaned some corrosion I had found.. it looked great afterwards. Installed it, still nothing. Checked for power coming out of the harness, The amp is getting power. There is a red light coming through the Fiber Optic connection. The only visible light inside the amp is a solid red light, no signs of yellow. Looks like I need to stomach the cost of a replacement amp at this point.

[ctuna]

repair here

http://www.bmwlogicseven.com/?p=3837

http://www.bmwgm5.com/Logic7_6941681.htm

You can find them on ebay and on the buy and sell board
here.

[Stage5Lurker]

Have you checked to see if the fiber optic came undone under your dash? I had the same issues until i finally check the connection under driver's side dash between column and obd. it simply cane unplugged.

[Dr///M3]

if your amp is bad could this cause a complete shutdown of the nav. my screen stays blank and i have no sounds, no gongs, no pdc, with sos inactivated. trying to see if i need a new headunit or amp.

[ptpending]

you should fix your sunroof drains before amp replacement or your next amp will die too
the repair with cost more that 200-300 is not reasonable because plenty of amps on ebay in that price
and repair of the flooded unit is not possible due the pcb damage

[335i_GP]

Luckily my car doesn't have navigation or idrive or anything. I ended up going the cheaper route, and removed my amp completely. I put in a $70 aftermarket Pioneer Headunit that I got on sale at Best Buy and wired it in and ran some speaker wires to the amp connection in the trunk and connected them there. Not utilizing the logic 7 system or all of the speakers, but hey its better than nothing and cost almost nothing.