I own a 2001 Altima GLE Limited Edition. It apparently has two horns (and possibly 2 alarms?), I think. The alarm annoys me, so I used the button under the hood to disable it so that now I see a solid red light letting me know it's disabled. To the right of that red light is a another light which blinks every 3 seconds.

Anyways so now I don't hear the alarm whenever getting out or in the car. When I lock my car it honks and flashes. Every now and than, about 1-2 times a week, the car's alarm would just go off for no reason. I would have to press the "lock" button on my remote to unlock it. So far whenever it has gone off I have luckily been within a close distance.

I suspected the battery terminals. 2 weeks ago it refused to start and once i pulled the keys out of the ignition, a VERY quiet alarm starting sounding. I messed with the terminals and the car started fine.

Now I need to figure what's causing the car alarm to go off and if there is a way to completely shut down the alarm.

Thanks.

Find the brain of the aftermarket alarm and unplug it. This should disable the alarm but make sure it is not armed or going off while you remove it.