brake lights not working

have you tried looking at filaments in the bulbs? there are 2, if 1 is broken that can be the problem,since your tail lights are working..

look under hood,big black plastic box,with round knob on top,there are relays in there don't mess with them.check from brake switch back up under dash,may find a break in power wire...........good luck

The brake light fuse and relay for the 2005 Cadillac CTS is located under the rear seat on the driver side. The fuse and relay is marked BAS fuse and BAS relay. See full article on Google Plus - "CTS Cadillac Brake Light Not Working - 3rd Brake Light OK." These guys don't use traditional fuse names because they want you to bring the car in for service.

I found a blown I IPoutlet fuse to be my problem

One fuse box under rear seat another in truck in car battery compartment

Can you rewire Brake lights on 2004 Cadillac CTS bypassing connection to the EBCM (Electronic Brake Control Module)?

The third brake light on the trunk gets moisture in it and causes a short. On mine I smelled it burning. Their fuse is located underneath the backseat. But you have to disconnect the third brake light or replace it by taking the whole license plate bezel off just to replace the third brake light off that bezel. Or you can cut the thick yellow wire that goes in the trunk lid that plugs into the bezel which wire's the license plate lights in the third brake light if you cut the yellow thick wire third one to the end it will cut power off that brake light