I have been looking through previous issues but couldn't find someone with this problem. I have a 2007 R56 MCS 80k. 2 weeks ago the drivers side airbag warning light came on and now stays on everytime I drive it. However, last night I went to someone's house and stopped outside whilst waiting for them. I turned the engine off but radio left on. When I went to start the engine again all electrical power went. I could not eject the key fob, no radio, no lights NOTHING. Whilst having a look around and under the bonnet, I noticed that when my wife shut her door (pass. side) the headliner lights flickered. I asked her to repeat the door slam and the car came back to life and I was able to start it... Airbag warning still on but no additional problems. I tried to recreate the problem when I got home but couldn't. Brand new battery 2months ago so it can't be the battery. Any ideas??

 

These three junction boxes inside in front of the passenger door, probably a short. Check for wetness while your in there, wouldn't be the first time I heard of it.

 

Plug in and read any faults that are in the system. It could definitely be something loose. Possibly a loose ground or connection at the battery..? Also, I know weird electrical things will happen with a bad battery so it might be a good idea to test it, just to rule it out of the equation.

 

+1 thats my bet also , that there is a short or cut on the harness.

Let you know what you find.

 

Thanks for all the replies! I ended up taking it to BRRacing in Los Gatos (they have been very helpful with the issues with my Mini). They could replicate the issue straight away, turned out to be two loose wires from the battery that was causing a short. They fixed the wires and it has been fine since.

 

Knew it, glad you were able to get it fixed.