2004 Mercedes S430 W220 Security system goes off intermittently overnight.

[ron59b]

Good evening all,

I have a 2004 W220 with 180,000 mile. Recently my neighbors mentioned that in the middle of the night my alarm system has been going off. The horn blowing, lights flashing inside and outside of the car. Each time there isn't anyone near the vehicle. Any suggestions of where to start? Is it possible to reset the alarm system?

I'd also like to know the location of the auxiliary battery? Would a weak auxiliary battery cause the alarm system to go off intermittently?

Thank you for your reply.

Ron