I've been chasing this issue for months now with the dealer. Intermittently the car will not start. I turn the key, and you just hear a click as if the battery isn't strong enough to turn the engine over. This can happen if I drive to the store get out the car, and 5 mins later try to start the car. It happens randomly, and while experiencing this issue, all electronics work, horn radio lights dash etc.

New battery, new alternator, randomly doesn't start, but if you let the car sit for a bit, it starts right up as if it never had an issue. Usually jump start the car when this happens and that works. Any ideas?

 

If you have a manual transmission, there is an interlock with the clutch pedal. Could be something in that circuit. I've had previous cars that I had to change the clutch interlock relay. First time that happened, I had already replaced some other parts as you have.

 

Nope, auto.

 

What is the year, make and model

 

05 545i

 

this happened to me before, seemed like those quick stops to the store is when it happened often, just as you mentioned. But now i always push the key in and wait for my airbag light to turn off in my HUD, which takes like 3 seconds and voila! it starts. my problem is solved. hope it helps you! good luck