Try disconnecting and re-connecting the battery cable.
On my 99 Suburban, the alarm activates when you press the lock button on the remote twice.
make sure ALL the doors are closed
You should just be able to "unplug" the annoying alarm similar to a turn signal flasher usually located either in or by the fuse block under dash on driver's side.
To disable the seat belt alarm on a Chevy Colorado, locate the alarm fuse. Pull out the fuse to disable the alarm.
The easiest way to disable the 1998 Chevy Lumina factory alarm is to remove the factory alarm fuse. The factory alarm fuse can be found in the fuse box.
It may be a low battery on your remote or even your vehicle. Well at least the some of the reasons.
Go to seat belt alarm stop.com
take it to a Chevy place
Tough luck. Take the car to a Auto Store. Theres nothing else to do about it. That's my only advise. Take it of leave it. Come back soon Thanx NOT
It means it works Security alarm
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The alarm is cutting off power to ignition and/or starter. Possibly faulty alarm. Disconnect the alarm and try again.