2002 Lesabre, security light goes on/off with "ding,ding" while driving?

The body control module controls all of your freaky problem. Replace that.

you will need to change the switch on the brake peddle. sits behind the cover. this can happen in an emergency and you also push peddle to the side wile ding it.

have alternator and battery tested sounds like one of them is faulty

Check our this link. Explains the security light and how to fix it. http://vatspasslockpasskeysecurityhelp.yolasite.com/

This means your master cylender is low on brake fluid , top it off with brake fluid and that should solve your problem . You should find out where the brak fluid is going .

The security system (VATS/PassKey) is dying - same that happened to me. You can find a great write-up here: http://newrockies.ca , it was the only thing that saved my Park Avenue.

Have you checked the fluid level in the master cylinder?

you have one of two problems the first one is either a blowm fuse that is probably marked prk lghts check you fuses or you could have a bad light switch

This could be a simple door adjustment. Have someone sit in the car while you push in on the hatch. See if the light goes off . If the light goes off, then adjust the striker plate so the hatch closes tighter.

Do you have check engine light on???if so scan it OBD 2 yue$$ding isn't the way to go,if you don't have a check engine light on then perhaps coil pack!!! coils do run intermittent some times! and not trip the eng light on !!!!this would be a great place to start.Hope this helps