2005 Mustang Alarm Going off by itself
 

2005 Mustang V6 Alarm keeps going off.

I have a weird problem with my alarm going off by itself. When I lock the car, the horn sounds once and the alarm is set. Normally there is no issue. I have a JBL Bluetooth speaker that I use for a speaker phone in my car. When the battery gets low, I have a USB charger that I plug into the cigarette lighter socket, on the dash, above the radio; I have been doing this for years, and I usually do this while I'm driving the car. Recently, I noticed that the speaker battery was getting low, so I plugged it in to charge, when I got to work, and locked the car. The cigarette socket is always active, even when the car is off. I then went into my office. A few minutes later, people are telling me that my alarm is going off. I thought at first I had accidentally hit my panic button on my key fob, which I have done in the past. I turned off the alarm and went back to work. A few minutes later, the same thing happened. This time I gave the key fob to our receptionist in case it went off again. I also couldn't accidentally set off the panic button, because it was laying on the desk. I continued to go off. The horn would sound for a bit and then stop and the lights would continue blinking. I then went to the car and unplugged the Bluetooth speaker so that it would not charge anymore. I locked the doors and went back to work. Now here is the weird thing; the alarm never went off again while the speaker was not charging. A few hours later, I again plugged in the speaker to charge. The alarm went off again a few minutes after I locked the doors. So it appears to have something to do with current draw while the car is locked and the alarm is set. I then checked the battery and it appears very good. The battery is only a few months old anyway and it starts the car like a champ. When I got home, and had the car in my garage, I again plugged in the speaker to charge and went into the house. No sooner did I get into my kitchen, the alarm went off. I unplugged the speaker, set the alarm and went back into my house. The alarm didn't go off again. I also checked the hood switch to see if it was working. With hood open, I couldn’t set the alarm, which is normal. I pushed the switch with my hand and was able to set the alarm. So I don’t think it is the hood switch. I also always keep the car in my garage and everything is very clean and dry. For a 2005, it looks like a new car.

Any ideas?

Thanks, Sheldon

only thing that occurs to me, is maybe try a different USB adapter.