After using a rented trailer the security light is now on steady on the message center. How do you turn it off?

I'm having the same problem with my Silverado.... I can still drive it but the headlights, dome lights, cargo lights, and guage lights don't work.. I have tried everything and the security light wont shut off. I know this isn't an answer to your problem but If I solve my problem, I'll be sure to let you know.