I've had some problems now and then with my Z4 Coupe that it would not start. Did run a diagnostic last year but nothing came up. Just some communication errors that we did not find any answers to. I think also my Intravee is making some mess.
So I started investigating a little
In the video below you can see that when I move the key from step 1 (acc) to step 2 (ign) sometimes only the airbag light lights up in the ign position. When try to start the starter kicks in, but that is it. So there is no difference between acc and ign.
If I take the key out and try it again it usually works fine.
Here you can see what happens:
So I asked my mechanic what it could be. Try to change the ignition switch he said. Its just the last part that the wires goes in to. Its not the complete lock.
Ok. so I first checked how much a new one would set me back. Almost 120$. Yeah right! So I bought two used ones for 15$ (for both). Bought two if one of them would fail.
Then time to do the change.
here you see the two switches.
Its no. 3:
http://realoem.com/bmw/showparts.do?...84&hg=32&fg=30
Off with the bottom part of the steering column. Its only one screw just beside the lever for adjusting the steering wheel. Then wiggle it a little to get the two pieces to part.
Here you can see the ignition switch where the wires is connected.
Just pry the little lock to disconnect it.
The switch is held in place by two small flathead screws that is located under the red screw locking paint.
Just loosen them a litle and pull out the switch. Put in the new one and fasten the screws and connect the plug. Now you can do a test if its working as it should.
It looks like I found the problem and got rid of it
I put some screwlock glue back in the holes and reassembelede the steering column. Now its to hope that the problem stays away.
As the nosy person that I am I had to open the old switch to see what was wrong. Looks like its wear and tear on the plastic.
The second step (ign) is the two brass parts on the right side of the 3 contacts.
A little video of how it works: