Spark Sensor and Ignition Switch
My 2006 X5 died. It would crank but not start. Technicians at Autohaus in Encinitas found a faulty spark sensor. Started immediately upon replacement but after turning off, it would not start again. Replaced ignition switch and now all is good. The ignition switch also affected my cruise control, computer, and battery warning light. Cruise would come on and turn off randomly. Then it wouldn't come on at all. Ignition switch was key - pun intended!! Check it out if you have these symptoms.