I just purchased an 89' 560 SEC. The alarm goes off by itself, with the doors locked or unlocked. What is going on ?. Any help would be great.

 

I know this is almost 2 years later, but hopefully this will help someone who searches in the forums for this.

I had this same thing happen to me with my 1986 560 SEC. I pulled the fuse for the alarm to keep it from going on but once the fuse was put back, it would go off again. So, I completely disconnected the battery overnite and when I reconnected it the next day the alarm worked again and I've not had any problems with it again for 6+ months. I'm assuming the computer just had a hiccup and needed to be reset. Of course, you'll need to get your radio reset if you do this unless you can just pull power from the computer.

Hope that helps someone.