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Alarm system going off

The alarm system on my 1999 Pontiac GP has recently started to go off randomly, and usually in the middle of the night. It started after I had the right rear window repaired as it was not working (going up or down) but the repair shop assures me that they did nothing that would cause this problem. I understand that this could be coincidental.

I am now forced to leave the car unlocked as my neigbors are getting testy.

Also, my drivers side window has suddenly stopped functioning and will no longer go down. The switch is dead.

I have 46K miles on the vehicle so it doesn’t seem to be an over usage problem.

Any ideas as to what might be the problem?

Thank you

Perhaps others read this and don’t make the same mistake, we must know the type of alarm and if it is factory installed,Dealer installed or “stero shop” installed. In general two things cause unwanted alarm activation,a shock sensor that is too sensitive or somehow the alarm senses a door opening (by activation of dome light) third and way down the list is alarm module failure.

started to go off randomly, and usually in the middle of the night. I Could be temperature related. A sensor may be a little too sensitive and as the temperature goes down it may trigger an error.

This is a factory installed alarm. Interesting about the temperature as the four times it has gone off it has been at night. I have left it armed during the day and no alarm.

Is this a big fix potentially and are the sensors easy to change?

Thank you both for the imput.

Is a shock sensor part of this factory installed alarm? if yes find it and lower the sensitivity. When this alarm is armed(and door locked) and you open the door (by leaving the window down and unlocking the door from the inside,we don’t want you to have to break the window for this test) does the alarm sound? I am trying to determine if your alarm is set to notice door openings as not all are.

Yes there is a shock alarm. Vibration will set it off and the horn and lights come on for about 4-5 beeps.

And yes, the alarm does sound when it is armed and you open a door.

Do you see a knob on the sensor that can be turned to lower sensitivity? with the window down and the alarm armed hit the steering wheel until the alarm sounds or you get a warning “honk” to get your inital baseline, then lower the sensitivity.

I don’t know where the sensor is so I can’t tell. Can you please tell me where to look for the sensor module.

Thank you.

My wife’s 99 Alero’s factory alarm does the same thing - only at night - whenever the battery runs down on the remote. Replacing the run down battery makes the problem go away til the next time.

On the remote? You mean the key fob? Mine is in the house in a drawer when not in use and the car is in the drive way, about 25-30 feet away. I have a six week old battery in the car so it isn’t that one.


If it was Dealer installed (and by me) the shock sensor would be tied to the lower part of the steering column. I was with Chevrolet in 99 not Pontiac but my idea is that there is not a cooresponding body platform for the GP in Chevrolet. Typically the factory likes to put them in the trunk near where a antenna would mount, but I cannot picture one even in a Cavalier or a Lumina,Malibu,Impala, Corvette yes, Pontiac had many more options of this type though.

You do verify that the alarm will sound when you “impact” the car? This search for the sensor could all be for nothing as the problem could just as easily be related to a incorrect signal indicating the door is being opened when it really is not. Almost a case for someone staying up all night and watching what conditions are present that are causing the alarm to go off,perhaps a monitoring camera?

EDIT: I cannot find any publication that states the location of the shock sensor.