Ok here's what I'm trying to do. I want to make sure the I've got this right before I start cutting wires. It looks like if I splice a switch in to the wire that is coming out of point 8(black/blue) on the ignition switch that the car will only start when I have the switch active and if I want to turn it into a push button starter I can disconect the wire on the ignition side and run a seperate power source to the switch.

 

And you want to install a kill switch because?
You know there is a chip in the key that the ECU must 'talk to' before the engine will start, right?

 

Well here's the back story to what's going on. I basicaly forgot my apt keys in the dead bolt of my apt door a couple of nights ago and the next morning they were gone and some how all my stuff was still here and car was not stolen. So I'm thinking some kids grabed them just to steal them. I have had my apt lock replaced and was going to do the same for the mini till they said that it would be 600 dollars just for the lock kit. So i've been disconnecting the battery every night till I figure out what i'm going to do. The two cheapest options I see are get a different outside lock and have two different keys but it keeps people out of my car or the kill switch which will stop them from taking the car but not keep them out. I havn't hit up the local junk yards yet but will tomorrow and bmw refuses to sell a different outsde lock from the one that is in the ignition.

So long story short the immobolization chip doesn't help me right now.

 

Don't you have insurance? Homeowners/renters insurance should cover everything above the deductable. I would bite the bullet and just get it rekeyed.

 

I actually do not have renters insurance. It was something that I always thought about getting but never got around to it.

But back to the problem at hand is that the right wire to be messing with?

 

So from looking at the two main post that seem to be linked in my searches and looking in the Bentley and Haynes manuals. The wire you want to mess with is the #8 connector that sends the start signal to the immobilizer. Even though the connection points are not referenced in the post mugami had the right idea.

Here's the laid out way to make a kill switch or a push button starter.

Kill Switch: Splice a switch in somewhere along the black with blue striping wire that is connected to pin 8.

Regular Push Button Start: Cut the black/blue wire and have the part that goes to the immobilizer go to the switch and then have a 12+ power supply wire go to the other side of the switch. You could use the power coming from the 6 connector. This will make it so that the car will only start if the key is in the on position and then use the button.

Back Up Push Button Start: Same as above but instead of cutting the wire splice into it. It's basically a combination of the two above. With this option you can still start the car with the key or you can use the button.

Hopefully this will help the next do it yourselfer that wants to take on one of these options.

 

Why not just put a kill switch right at the battery? I know they are available (there was a thread about these a while ago). Much easier than messing with all of the ignition wiring.

 

I thought about doing that as well but the car doesn't seem to like having the power cut every day. When I first hook it back up in the morning and I try to start the car it stumbles. Then I turn it off then back on and its ok. That might be a unrelated problem.

I also wanted to do something that is not as obvious as popping my trunk every time I go to the car. I will most likely go for the lock set on my next pay check but want something to stop them for now. Once I get the set maybe rewire it into a regular start button.