2004 Elantra, bought used this year with no documentation (checking ebay now for owner & repair manuals). The last couple of days - intermittently the audible car alarm siren will go off in the middle of the night. I don't know if this is a factory or aftermarket alarm.
No other electrical or mechanical problems I'm aware of at this time.
1-Does anyone know if this would be a factory or aftermarket alarm system? Did 2004 Hyundai Elantra use the cars horn (as U.S. cars do) for the audible alarm if factory installed (this one has a siren)?
2-If this is a factory alarm, where can I get a schematic/wiring diagram for this?

Any help would be appreciated.

This post has been edited by pnpk: Nov 23 2009, 08:08 AM

If i am correct that year car used a siren as opposed to the horn. there could be a few diffrent things that are wrong with the car you coul dhave a bad door trigger which would not allow the alarm to arm so scratch that off your list unless it is not completely broken possibly a bad solder joint or just a bad connection depending on where your located a change in tem from warm to cold could possibly cause the connection to shrink and thus not having connection and more and making your alarm go off. Your hood pin could be bad and wind moving could cause this to not have the propper connection or your hood could be popped but not open and only your hood pin being down slightly. Your battery could be starting to die over night as well. If it were an aftermarket alarm you my be having some of the same issues or the shock sensor could be going off. The best way to locate and see if it is an after market or factory alarm is to look under your dash and just see if there is any wiring that goes to your ignition wires that mya look non factory. If thats the case i would bring it to a local Car audio store for them to look at the alarm and possibly determine what kin it is and if they can service it for you. Hope that helps a little bit if not sorry i tried feel free to pm me

Thanks for the post TAP. I did find a sticker on the drivers window, says something like...Warning Alarmed by Hyundai... I also found the hood pin, and the wiring to the hood pin looks very much like factory wiring harness. I have unplugged the hood pin, to see if that is the culprit...??? I have also been parking the car in the garage, so it doesn't disturb the neighbors.
I'm in Cleveland OH, so the weather is starting to get colder but parking it in the garage keeps it a little bit warmer through the night. I've had 3 nights so far, parking in the garage with the hood pin unplugged that the alarm has not gone off. That hood pin sounds like a dealer part (big $$$)??? I think if it was the battery, I would still be having the problem.... I guess my next step is to price out (and replace) the new hood pin..........

If it is the hood pin it shoul dbe cheap and honestl if your not worried about under your hood you can leave it unplugged it will just not warn you of your hood being open thats all but yeah go to the dealer it shouldnt be an expensive part and if it is you could always try your local junk yard for one