My 2001 tahoe alarm keeps "auto" arming itself after about 30 seconds. How do I stop it from "auto" arming? Its driving me crazy

This alarm works with the remote and the key, if you lock with the key it arms if you lock with remote it arms,when you unlock it it should disarm, if your having a problem with it not working try the pass/side lock with key, that should shut it down but if it keeps rearming without locking doors then it may be aftermarket, also in your manualy it will show you that some factory alarms are also self arming this is programed through the cluster, using the buttons on the dash, you scroll through the options and shut off auto arming, this is done the same way you scroll for mileage or trip time or oil change life. hope this helps.