BMW Repair: Alarm System False alarm 2002 540i, tilt sensor, negative battery

Question
I tried disconnecting the interior motion sensor under the headliner but the system still will go off with no apparent reason.  The alarm only does this when I park it at home and a few other places. I can leave it parked at home in the parking lot for a few hours then at 12 or 1 o'clock in the morning it will trigger itself with no one anywhere in sight. Sometimes it will just go off as soon as I disarm it and rearm it again. Do you know what could be causing this?

Answer
Jermaine, very hard to tell without looking the car over myself. I do see a lot of faulty hood and trunk switches causing this problem. Also Please make sure your vehicle battery is in good condition. Undervoltage will cause alarm activation. If the negative battery post has an "02 or O1" depending on when your vehicle was produced it is an original battery date stamp. Four-Five years is about the average life of a Factory battery. Occationally I will come across a bad Siren unit. There is also a possiblilty of the Tilt sensor being fault (never seen one bad personally). Lube your door latches to make sure they have full travel and aren't hanging up. Dealership does have some diagnostic fault memory for the DWA (factory alarm)system. This diagnostic memory will tell you the last few components that triggered the alarm. Well those are all the options that I can think of off hand Jermaine. Best of Luck
-Evan