Car Alarms: Grand Prix Alarm, car alarm system, spark 2

Question
QUESTION: The past two mornings at about 9am local, my car alarm
horn has started blaring...while yesterday was windy, it
was not worse than other times, and today is perfectly calm.
What could be the issue here...there is no person, or animal
around the car, so no reason I know of to set the alarm off.
thanks
don

ANSWER: Please be more descriptive if possible.

"GOING OFF?"

I need to determine whether it's a factory alarm
issue or, if it's an aftermarket system you are
dealing with.

Ok let's clear up the terminology glitch here.

1. FACTORY/OEM alarm = Part of the original schematics
and plans from the manufacturer.
(horn honk, head lights flash, Starter may crank and
die, no spark)

2. DEALER INSTALLED alarm = Just that. Once the vehicle
is brought to a dealer, the dealer sub contracts the after market
security out.
(horn might honk, siren and parking lights flash, starter kill relya,
no start, no crank, just dead.)

3. AFTER MARKET alarm: Same as #2 but Customer IS AWARE that
the system was put in at the dealership, but may not
be informed of the brand name, or even what it's
total capabilities are.
(siren & parking lights flash, starter kill)

Which one applies to yours?

RM/ALARMTEK
CARALARMMAN.COM

---------- FOLLOW-UP ----------

QUESTION: Number "1" applies...this is factory oem car alarm system.
Horn sounds, lights come on . Thanks
don

Answer
Ok, Chevy/Pontiac/ALL GMC "alarms" depend on battery level.
If the vehicle see's a spike 5% either way (usually drain), it would
set off the car's horn and flash the headlights. Turning the key
in the drivers or passenger door, left, then right would disarm it.

This is the normal reaction to a bad or, not up to snuff battery.
(Unless there is damage to the door pin switches of a light bulb
out in the vehicle, my guess is the battery needs to be replaced,
not just recharged.)

This should correct the "there is no person, or animal
around the car, so no reason I know of to set the alarm off."

Oh FYI... Chevy car alarms do not have shock/impact/vibration sensors.
Just detect battery drain/levels, like when a dome light comes on.
So replacing the Battery is the fix here I'm thinking.

GL. ;>)

A.