The bottom tail light on start up won’t bother coming on. But when it comes to locking and unlocking the truck it will. I was thinking it’d be fuze but if that was the case the whole bottom light wouldn’t work at all. It’s a 2018 Silverado 1500 with 30k miles on it. I’m not sure if the temperature comes in to play with it being constantly -10 - -40 degrees here all the time. It works whilst driving, but it’s only on startup that it chooses not to work.