My hyundai sonata hybrid has been acting weird for a couple of years. It would randomly starting alarming without anyone getting close to it. It does this late at night or early morning, in the afternoon and during the night. I have brought it to the Hyundai Sonata dealer and they could not find what is causing that. It does this daily while I am at work and cause a great deal of embarrassment in my parking lot. There is no accident and the doors are often tightly locked. I have just replaced the battery but it continues this daily alarm. Anyone has an idea what is causing this?

 

Is the alarm system factory installed or aftermarket?

 

A bad connection at any of the door, hood, trunk switches, A bad computer, The computer will set off the alarm when there is a voltage fluctuation, I have caused this when jump starting a vehicle from mine while it was locked up, I am not sure if there is a movement detecting switch(bump switch) somewhere, as I have not seen it.

 

The alarm is factory installed. There has been no change to any component of the car except the tires. I bought it in 2014 as the second owner and didn't have any issue with this alarm until about 2 years ago when the random set off started.
Pls help.

 

I have troubleshoot many times; the door, hood, etc. All appear to be closed tight. I have no idea what the trigger is as it happens inside, outside, anywhere. Often time, there's non=one within the vicinity of the car.
Please help.
Thanks.

 

Try this:
https://www.hyundai-forums.com/threa...isable.499553/

 

If you have a remote to turn it off, when home and convenient, stuff a rag in the horn , then remove the battery from the remote and see if it still goes off. Al least you will be able to hear it without a lot of noise and still have time to put the battery back into the remote to stop it. What do you think?