[sonick]

I am wondering if somebody could fill me in on how the TCU and mulf2 high are wired from the factory?

I just got a used BMW that did not have the Aux/USB working, and I think the previous owner did something with the mulf2 high unit.

When I found it, this is how it was wired up:

TCU
Connected: White 54-pin plug
Connected: Black 2-wire Optical plug
Connected: 4x antenna wires

MULF2 High
NOT Connected: Blue 54-pin plug (the
Connected: Black USB plug
NOT Connected: Beige circle plug (coax?)
NOT Connected: Black 2-wire Optical plug

Also noticed a bypass loop was plugged into one of the 2-wire Optical Fiber harnesses.

Also, the blue 54-pin harness for the MULF2 High only has 6 wires going on, four of which I assume are the ones for the Aux. The other two I assume power? Is this normal? Or should there be more? The white harness going into the TCU has a ton of wires.

Is the MULF2 high supposed to be also wired up (i.e. blue plug, optical plug) in addition to the TCU, or is it one or the other?

I have a suspicion the MULF2 High is faulty and the previous owner just bypassed it. Just wanted to confirm the factory setup before I look at spending money on a new MULF2 High.

Thanks!

[ctuna]

There are lots of threads up on this subject on the first page
of threads right now.

one of them is

https://www.e90post.com/forums/showthread.php?t=1553893

[sonick]

I've looked through several of them but most of them are talking about how to upgrade or retrofit the various modules available.

Instead, I just want to know how it is wired by default from the factory.

[ctuna]

https://www.newtis.info/tisv2/a/en/

You can look up any wiring diagram and some overall theorys
of operation at the above link.

https://www.bimmerfest.com/forums/at...9&d=1539905743

And to what purpose.
Yes it has to be plugged into both the Most bus and electrical connectors
to work. Is it there a mulf unit even installed. Cars up until 09 come
with factory pre wiring. There can be a lot of plugs with no modules
attached.
Do a vin check to see what was installed when delivered.
See georges list of links for vin checker.

You would be having error in the most bus if it wasn't
(OK bypass loop I get it)

electical e90 pdf
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU

[sonick]

Awesome, thanks!

[ctuna]

Mulf 2 hi are something like 70 bucks US on ebay right now

[sonick]

Originally Posted by ctuna

https://www.newtis.info/tisv2/a/en/

You can look up any wiring diagram and some overall theorys
of operation at the above link.

https://www.bimmerfest.com/forums/at...9&d=1539905743

And to what purpose.
Yes it has to be plugged into both the Most bus and electrical connectors
to work. Is it there a mulf unit even installed. Cars up until 09 come
with factory pre wiring. There can be a lot of plugs with no modules
attached.
Do a vin check to see what was installed when delivered.
See georges list of links for vin checker.

You would be having error in the most bus if it wasn't
(OK bypass loop I get it)

electical e90 pdf
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU

Thanks for the tip, yes looking at the VIN decoder it does indicate it should have the MULF2 High module associated with USBAudio Interface S6FLA.