There are signs that your BMW ignition switch
Not only your BMW, but all other cars' ignition switches are composed of two parts. The first part is in the front of the switch. This is a theft deter device that prevents the car from moving unless the right key is in the ignition switch. The BMW includes another system that prevents the engine or the starter motor starting mechanism from operating unless the key is in the ignition witch. This gives your car a bit more security. If the key is not in the ignition lock, the engine is not going anywhere. This same system is the one that makes the noise when you leave the keys in the ignition switch or when you open the door. This insures that your engine will not start until you put the right key into the lock. There are three options in the ignition lock. The first option is the 'lock' option which, as expected, turns everything off, and you can't even open the radio in this case. The other option is the 'on' option. In this option you may start most of the electrical devices in the car like the windshields, the heater, the air conditioner, the radio, the electric windows, and so on. The last option is the 'start' option. This option is the one that instructs the start motor to crank and breathe life into your engine.
The other part of the ignition switch is the electrical lock in the back of the ignition switch. This lock is right behind the ignition switch and act as the actual gate between the battery and all the other devices in the car including the start relay responsible for starting your engine. Trouble in the ignition switch can be very annoying if not indeed very dangerous. Your car can stop right in the middle of the high way road. This is why you need to take your car regularly to maintenance, and never ignore any signs of disturbance in the ignition lock. When it comes to ignition locks, it is always better to just replace the whole thing and buy a brand new lock. Go to http://www.lockbargains.com/locks_and_hardware/automotive/ignition-switch-locks.html for a great deal of information about ignition locks.