My tail will not come on when I press the break pedal on my 2003 Cadilac Escalde

there is something that senses that you pushed on the brake pedal and that something is broke.

Halo,check your brakelight switch above your pedal,you can test it by unplugging it,take the plug and bridge a wire from 1 terminal to the other,if it do comes on your brake light switch is faulty,it can be the inner contacts of the switch.replace brakelite switch

I was was being facetious and trying to lead Noony towards using their own brain for a change :)

This is very common! The reason this happens is because a wire that is above the back door breaks. I'm surprised that the people that builds these don't fix the proble from the very start! One day I'm sure a car company will come out with a product that fixes problems before they put it out on the street!