[Sprinterman]

The ambient lighting cable has little or no power, all my ambient lighting has failed apart from a tiny orange dot barely visible to the naked eye on the cupholder led. It’s possible the wire snagged or pulled during an MMI box fitting. My question is, is the wire connected to the headlight switch, I’m guessing it is as the ambient lights lit when you turned the sidelights or headlights on, I’m wondering if the wire came loose, but if it did the headlights wouldn’t work. Any ideas?

[NealfromNZ]

Google is your friend 😉

But light switches these days don’t carry the power for lighting. They send commands to modules that provide the power rail and logical switching between different colours if the car has multi coloured lighting.

Best way to understand it is to look through someone doing a retro fit.

Here is someone doing a 2 series retrofit. Have a read through to gain the understanding .

https://www.2addicts.com/forums/show....php?t=1776040

[Sprinterman]

Much appreciate your reply, I’m no further, the voltage from the ambient wire in the photo is or must be too low to power the LEDs in the doors etc. this happened after the 12v power socket under the glove box sparked and blew after I reconnected it.

[NealfromNZ]

Ok

Sounds more challenging. If a MMI has been added then I’d have a close look at the big square quad lock connector as the idrive is connected to the K bus. K bus will be used to send commands from the idrive to Fem ( Front Electronics module ) to turn up or down ambient lighting.

It sounds to me like you have power to the ambient lights , but brightness is on minimum but the commands to turn it up aren't getting through .


Make sure the piggyback arrangement between the idrive , idrive main harness and mmi are all mated correctly. The k bus connectors are in the mid section of the idrive connector. Also check that area to ensure no pins have been bent in the process of the install.

The first pic is where to look on the back of the idrive , the second is a system diagram. So in the second you can see the k bus between the cic ( idrive ) and the fem module that is feeding power and colour setting to ambient LEDs

[Sprinterman]

Again much appreciated, it’s definitely not any of the connections as the ambient lighting has been working perfectly for many months after the MMI box was fitted. The failure occurred after the 12 volt under glove box socket touched the chassis when I was putting it back, a spark and a bang blew the FEM 5 v fuse, wipers were permanently on, no headlights etc. I replaced it and everything worked again apart from the ambient lighting, the door card LEDs are off, the AC center console LED is off, only a tiny faint glow of orange from the cupholder LED. I’m not sure where the ambient lighting wire gets it feed from, I’m considering purchasing an OBD 2 reader and see if a fault code shows up for the ambient lighting, and try and reset it. Everything you wrote made sense but it’s not a connection issue. It’s definitely linked to the 12 volt blowing

[NealfromNZ]

Kinda amazed that the 12v outlet could damage the fem but scanning the car would be the only way to know.

Worth have a read of this though. From about late 60s pages it covers lighting.

https://www.bimmerpost.com/goodiesfo...ectronics1.pdf

[Sprinterman]

It didn’t damage the FEM, just blew the 5amp fuse in the FEM, replaced it and wipers back to normal etc. So I’ve scanned the FEM with bimmerlink, I’m getting the following, but it won’t let me clear the error codes, I’m guessing central fault memory full is the reason why? At least I now know what the issue is. Any ideas what to do next?

[Sprinterman]

Solved, cleared the error memory and fault codes with ISTA + not only did I get my ambient lighting back, I got both sport and classic mode, previously I was only getting classic orange. Now both are switchable again. Thanks for all your help guys