head unit wont switch to aux

[Aldous]

I have an e53 x5, i ran an aux cable to back of the cd player a year ago or so and had the aux input working since.

last week the head unit stopped being able to switch to aux, it just goes between radio and cd when pressing mode.

i pulled the cd player, unplugged and plugged the cable back in, didn't work. as i was putting it back together i hit the mode button a bunch of time and it went to aux however this morning it wouldn't go back to aux.

does anyone here know the mechanism by which it deteremines if there's an aux cable connected? i used to be able to switch to aux without an ipod or anything hooked up to the cable, so it's not based on receiving a signal...

any thoughts or ideas?

thx

[fmugur]

Check this link... It might be a connection problem to the 300K resistor.
http://www.xoutpost.com/bmw-sav-foru...e-missing.html

[Clockwork]

Originally Posted by fmugur

Check this link... It might be a connection problem to the 300K resistor.
http://www.xoutpost.com/bmw-sav-foru...e-missing.html

This link was a massive help, for me.


Sent from my Pixel 6 using Tapatalk

[Aldous]

thanks fmgur,

finally got around to fixing it yesterday.

there's a small circuit board inline in the flexible aux cable (pretty awful design). i guess some motion or bending of it popped the solder off of the board on one of the connections. had to resolder the connection and now it works

[bcredliner]

Good work--great when the first look is the cause!

[bcredliner]

Good work--great when the first look is the cause!

[g300d]

Yep, that circuit board is the resistor that the system looks for to activate AUX mode.

Good to see you got it sorted out without needing to go on a witch hunt.

[Clockwork]

same fix required here. I tested the inline motherboard's resistor and it was showing 297k ohm, but maybe thats just not enough, so i soldered a 300k ohm resistor between the white with blue stripe and white with red stripe, about 3 inches cack from the black plastic harness connector. voila