Third Light on 2005 GMC Yukon XL 1500

I Have a 2005 yukon my third light is out, is these a item that i can replace the bulb or do i have to replace the whole piece...????

Asked by for the 2005 GMC Yukon XL 1500
I believe you must change the complete third brake light assembly on your 2005 GMC Yukon XL. Checking with your local GM parts dealer would confirm this.