Factory alarm goes off for no reason

If that system had no problems, it would not go off

So there is a reason,find it,check for codes & do some testing

It can be any of the car door not got properly locked or the door is locked but the switch is not sensing the door locked.Open and close each door again properly.
Or else its problem with any of switch wiring getting in contact with alarm wiring causing it to happen.And last thing alarm connections needs to be inspected.Its getting short somewhere in between.

There are few helplinks with solutions,to troubleshoot these types of problems.I suggest going through these links.
Click the link below:------Volvo car alarm keeps going off for no reason http://technoanswers.blogspot.in/2012/07/volvo-car-alarm-keeps-going-off-for-no.html
------------------ Alarm keeps going OFF http://technoanswers.blogspot.in/2012/07/alarm-keeps-going-off.html
--------------2009 Toyota Camry: Hood Switch causing Alarm to go OFF? http://whatisbyme.blogspot.in/2012/04/2009-toyota-camry-hood-switch-causing.html
----------------Ford Pickup Alarm will not disengage? http://technoanswers.blogspot.com/2012/01/ford-pickup-alarm-will-not-disengage.html
------------Mitsubishi Diamante: Factory Security Alarm will not go Off http://www.howtorepairguide.com/2012/11/mitsubishi-diamante-factory-security.html
------------Toyota Avalon Factory Alarm will go off? http://repairhelpcenter.blogspot.com/2012/01/toyota-avalon-factory-alarm-will-go-off.html
----------Chevrolet Tahoe Hood open warning on dash and alarm sounds? http://schematicsdiagram.blogspot.com/2011/12/chevrolet-tahoe-hood-open-warning-on.html
-----------These details will help.Thanks.

50 degrees and it's just sitting there or is it riding down the road? sounds like the battery is going down and as it goes below a certain voltage the alarm goes off. Show up at a parts store and have them test the battry and for a battery drain( draw09 a darw on the battery as the car is shut off. This may find the reason for the alarm going off.

if its an aftermarket alarm, which im sure it is, find the brain to the aftermarket alarm and unhook it. trace the brain back from the car alarm siren hardware. it shoud b mounted somewhere under the hood. theres not a lot of available space in the engine compartment. so you should easily find the siren hardware. trace the wiring back to the brain and disconnect it. it cant be factory alarm. factory alarm only goes off when u dont use keyless remote or key to unlock a locked door or trunk. factory alarm blows horn and blinks parking lights

somebody that you are parked close to has a after market alarm or your alarm box is bad diconect the alarm box for 15 miniutes and then connect if it still happensx your box is bad

take it to another suzki dealer cause if u hear an alarm going off and they say your car does not have a factory alarm this is a major issue ethier the guy looking at the car at the dealership does not know much about alarms or he is just a salesmen i know some suzuki Forenza come with factory alarms

Do you have a (FOB) for your car, if so use the unlock button

disable the hood microswitch. just unplug it. That and the cabin sensor are the most probably reasons the alarm will go off.
Alarms are useless. Totally effin useless. So it goes off.....then whaddya going to do. Shoot someone? Call the police? or listen to it drain the battery over and over again.
But....you can't disable the alarm totally. The bmw engineers have tied it into the main computer. you can however disable the sensors one by one so it doesn't set off the alarm. Hood sensor....Hood sensor....that's the culprit.

check with your local dealer, there where having issues with that and i know they found the fix for it.

Set the alarm and sit still in the veicle. Just before the alarm goes off i would expect the door ajar light to come on with the alarm. It sounds like a faulty switch making the car think somebody is breaking in.