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sam vu
09-22-2012, 11:33 PM
i own a 2004 bmw 745i , the navigation system , radio system, are not working anymore, the fuses are all good, i was wondering if any one out their knows what the problem could be? please let me know thank you,

i do some research and find out is it the voice input control unit problem ? if anyone hve the same problem and already fix ,PPPPPPPPPPlease let me know.

KaileSvick
09-23-2012, 12:28 PM
Sounds like a fiber optic problem. One of the units in the loop is not functioning.

SFbay
09-23-2012, 06:00 PM
To find out the actual bad module(s)
You need to find where your fiber optic light stops emitting: disconnect L7 and check if it has the light, then if it does, go to next module if not then previous module is bad- the last most bus checkpoint is in your glovebox: if it has the light in there it means all most devices are good and transmit the light creating closed circuit.
The start point is your MMI screen
The last one is your glovebox jumper.
And it's the easiest and most efficient way to diagnose that most bus,i developed when I could not find out the bad module by bypassing with the jumper. otherwise you just blindly bypass each module with the jumper until you find the bad one, but if you have 2-3 bad modules it's not easy.
Most common modules are:
Voice module
L7
Telephone
Navi

Other modules are kinda more reliable..
P.S.: To someone who said I get all my info from google: try to google this method anywhere.

sam vu
09-23-2012, 07:00 PM
thank you all you guy , i will try to find out what module problem.
do i have to buy Fibre Optic Loop connector or how can i make one ? please tell me how if you know it.

SFbay
09-23-2012, 07:27 PM
thank you all you guy , i will try to find out what module problem.
do i have to buy Fibre Optic Loop connector or how can i make one ? please tell me how if you know it.

Better buy one from the dealer. You can make one, but it's a real hassle, not worth it and its lousy connection.
But first find where it's loosing the light.

sam vu
09-24-2012, 08:03 PM
hi my friend. today i check nav and voice module find out everything is ok optic light go throuht very well up to glovebox tommorr will try L7 then mmi sreen . do you guy think it maybe cd changer or sigle cd ? i will update later