96 Maxima horn and headlights came on suddenly

[Nonsmiley]

My son and I were outside when my 96 Maxima's horn came on. I looked over and the headlights were also on. I ran inside and got the keys and tried to lock/unlock the car using the remote to try to disable the alarm. Nothing changed. The horn wasn't intermittent like when the alarm sounds, but was on solidly. Also the headlights were on, although the switch inside was turned off. I tried disabling the alarm by turning the key to the unlock position and holding it, but to no avail. I finally opened the hood and disconnected the battery. An hour later or so I touched the cable to the terminal again and the horn began again. Not sure what has happened, car hasn't been driven today, no one was around or in the car or has touched it today. This began out of the blue with the car off and in park sitting in the driveway. I am not sure what the problem is, I think I will pull the fuse for the horn and reconnect the battery and see if it will start first and go from there. If anyone out there has any experience/theories on this let me know. I will try some more experiments to see if anything else is out of the ordinary. I would think it was just a problem with the horn or relay except for the headlights coming on too, it makes me think it might be a problem with the factory security system.

[Nonsmiley]

***UPDATE*** Ok, I got it 'fixed' at least for now. I'm not sure what happened to begin with to cause the problem, but I had disconnected the battery at first to silence the incessant horn blowing, and after a few hours I went back to figure out how to correct it. So the first thing I did was disconnect the two horn relays so that I could hook the battery back up and figure out what was wrong without annoying the neighbors. When I hooked the battery back up, instead of the lights being on steady as before, now you could hear the headlight relays clicking and see the headlights flashing like the normal alarm. The remote did nothing, but this time when I held the key in the drivers door in the unlock position for a couple of seconds turned off the alarm and so therefore the lights and horn. Problem solved!? Car started normally after that and everything worked, and I replaced the relays and the horn was off again. So I am not sure what happened and not sure what solved it. Maybe having the battery disconnected for a few hours was the trick, but who knows? This never happened before and hopefully it will never happen again. I hope this will help someone who may find themselves in this position in the future.

[maxhopper]

Welcome to NICO.

Glad you were able to resolve the problem for the time being. If it happens again, I'd suspect one of the relays on the passenger side of the engine compartment. If all of those check out, it may be an issue with the body control module itself.

You can find more info on the theft system starting on page EL-245. http://www.nicoclub.com/FSM/Maxima/1996/EL.pdf