[osand39]

So I recently bought a 06 330i. It has an aux input under the arm rest but it doesn’t work. I’ve tried plugging in different devices with different cables and I still don’t get the aux option in the audio menu options. There’s only Radio, CD, and USB. I don’t have a USB port so idk why that usb option is there and it’s not selectable. The cigarette port next to aux port works and so does the Bluetooth.

I’ve looked around and tried messing with the TCU/MULF to look for loose cables but no luck. Car also has L7 and everything seems to be stock. Any help would be appreciated, thanks.

[ctuna]

It's strange that you have USB
Because USB was not an option on a US car in 2006.

So I guess someone has modified something.
which means your car is modified somehow.
Do you mean bluetooth phone?
There was also no bluetooth music streaming available
with a pro radio in the e9x series.

[ptpending]

make photos of the cables connected to mulf/tcu and we try to guess what options you have
also you can provide your VIN number to check your car options list

[vilord]

The later professional radios moved the USB input from the trunk to the back of the radio.

Perhaps the previous owner replaced the radio (either because they wanted USB or because the display/something else on the old one died), and didn't reconnect the aux cable harness? I'd try pulling out the radio and seeing what sort of wires are going into the back of it, and also what part number it is.

Also possible that the aux plug in the armrest had cola or similar spilled into it and the sensor that triggers that a cable is plugged in is shorted.

[vilord]

here's what the later ones with USB look like on the back. The white plug is the USB port.