Can someone please assist me in finding out where I can purchase a 3rd brake light or have the one that I have on my car repaired at a reasonable price? Also is there a light vo.patible to the 3rd break light for the SRT-6 convertible crossfire, 2005 year.

 

You will find out all what you need with 'search'.

Try here: Replacement LED High Mounted Cadillac Third Brake Light, Brakelight, Third Brake Lights, For Cadillac Escalade ESV, Escalade EXT, Avalanche LTZ, Chrysler Crossfire, Lexus SC, 2010-2011 SAAB 9-5, 2015-2018 GMC Yukon Denali Tail Lamps

James

 

There is a post explaining how to fix the brake light, specifically it is half out.
Why postvin this forum? It is not for questions like yours.