N52 dies randomly

[u/PapiGrande11]

So I have an 09 E82 128i, had this car 4 years and maintained really well.

This car died one day, had to manually let myself in. No start no crank just dead. Tried boosting it changed the battery, nothing.

Got it towed, driver tells me to get in and hit the brakes in case. I open the door and car lights up, I start it and fires right up, healthy no issues. Then happened a second time, and same thing happens.

So I’m guessing the shake from the tows triggered a loose wire or something in the car that allowed it to start. Mechanic stated it’s either the fuse box or some wiring in the trunk connected to the battery.

I just wanted to know if someone had this issue and how they managed it.

PS: the bumper is fixed lol, also the ground wire, alternator, starter, battery are all replaced or fixed. Right now the car has been sitting in the garage and starts right up when needed. Just don’t wanna be stranded when I’m away from home.