So your going to make us guess the year and model?
Not a big deal with a little information.
Use a jumper wire from pin 11 to 12 and if the ignition is in the number two or run position then the engine will turn over if the starter is not the problem.
If it turns over with the jumper wire the electrical side of the ignition switch is bad. You can change just the electrical side of the ignition switch.
http://www.unofficialbmw.com/images/reset1.gif
1. Ground
4. Temperature sensor
7. Reset
8. TDC sensor yellow
9. TDC sensor shield
10.TDC sensor black
11.Start signal
12.Alternator charging excitation voltage
13.Ignition coil
14.Alternator charging supply current
15.Oxygen Heater
Later,