I was pulling my headline in my '04 R53 and encountered these wires and I was wondering what they are for. The one being held in front of the steering wheel came out of the left side A pillar and the other one comes out of the roof from the area of the antenna. They aren't attached to anything but I would still like to know what they are.

 

The one in front of your steering wheel is an ethernet cable, like what you would use to connect a computer or gaming system to a modem or router. I couldn't even hazard a guess as to why it's run through your headliner.

 

The wire in the headliner is factory prewiring for the optional (dealer installed) car alarm: http://www.billswebspace.com/MiniR53Alarm.htm

The ethernet cable isn't OEM and was something aftermarket done by a previous owner.

 

Thank you both for the quick and concise answers. I knew I could count on the NAM community.

 

That first one looks like what is used by some radar detectors such as the Valentine One and I think some Escort models. Coming up the A pillar is common to install the detector near the top of the windshield without have a wire dangling from say the cigarette lighter.

 

Yeah the phone cable style is for something aftermarket like radar detector, but also could be for a scangauge.

The 2nd is for sure the factory wiring to add the interior motion sensor for the alarm kit.