and the horn beeps when I turn the Yukon off. Can't seem to find the problem. Any help would be greatly appriciated.
Sounds like you have an aftermarket alarm installed that you don't know about and it is possibly on the fritz. You could pull the kick panel down below the steering column and look to see if you see a box 4"x3" zip tied to the steering column or just hanging there. It may say DEI or Code Alarm or may not say anything but it will have a mess of wires connected to it. Or just trace the wire from the blinking light back and I bet it will lead you to this box. If you do find the box, you could take it to a audio store and have them test the alarm and if it is any good, reprogram you a new remote and you just got a free alarm. If it is dead, have them deactivate it or remove it. I have removed them before myself, just be careful not to cut/remove the wrong wires!!
