third brake light not working
Replacing high-mount brake lamp bulbs
Your vehicle is equipped with an LED center high-mount stop lamp. It is
designed to last the life of the vehicle. If replacement is required, it is
recommended that you see your authorized dealer.
Owners Guide (post-2002-fmt)
Thank you. It looks like there no way to get to it without taken down the head liner.
you could partially take the headliner down. but you would need to replace the 3rd brake light assy. the light is LED and dont have bulbs you can change.