not sure of the Fuse controls but I just ordered a replacement LED strip from CARID. It's not cheap; like $80 of $90 but after watching a couple of YouTube videos felt comfortable replacing it myself. Just my 2-cents.What fuse controls the third brake light. Mine is not working and I want to try to see if it’s the fuse that is burnt out.
The 3rd brake light strip went bad in my Magnetic Gray Base. No problem in changing it out. Cost around $85 US. Then the 3rd light went out in my Liquid Red Base. When I went to replace it, I found the connector in the truck was disconnected. I'd had a bunch of stuff in the trunk a few days before and must have snagged it. Cheap fixes do happen, even with a G8!Unsure how the third brake light is tied into the electrical system. If no other electrical issues are present, then the problem could very well lie either somewhere between the wiring harness and the light itself.