NHTSA Complaint #11444443 — 2011 BMW 328I

The positive battery terminal connection on the thickest cable in the trunk of the car (this wire leads from the battery in the trunk to the fuse box behind the glove box of the car) was loose due to either natural loosening over time (i.e. loss of torque on the fastener) or improperly applied torque by various BMW service shops (battery was changed by independent BMW service shop in 2018 and checked by BMW dealership in 2019 to be in good health). The loose connection at the battery terminal on this wire caused the car to suddenly turn off while driving on the road. Once turned off, there was zero electrical response from the car (e.g. engine turned off, no headlights, no hazard lights, no power steering, no capability to restart the car, airbags likely would not deploy if car crashed, etc.). The car could only be controlled by coasting on its remaining inertia, slowed down using residual braking power (which disappears after applying the breaks 2-5 times due to loss of hydraulic pressure), and forcefully steering the car (since there’s no power steering). This is an INCREDIBLY DANGEROUS situation that could cause loss of life due to complete loss of control of car. Both the battery and alternator were in good health. Only the battery terminal connection was loose, leading to a single point failure of the ENTIRE electrical system of the car and the car itself. There is NO redundancy in the electrical system; even if the alternator is running fine, the loose battery connection will kill the car. Furthermore, once car is stopped and safely secured, it is EXTREMELY DIFFICULT to open the trunk to access the battery as there is no way to access the trunk manually via key. I had to apply a 12V source to the large red wire at the fuse box to power on the car, enabling me to open the trunk. This requires removing cupholders, glove box, various trim panels, etc. to access the fuse box. Absolutely terrible design.