After not driving the car (2017 gt350) for ~ 2 months I was left with a dead battery, did try jumper cables but was too dead, pulled battery and put on a charger. When I put the battery back in I no longer had rear turn signals and brake lights. (3rd light does work when I step on the brakes and tail lights work) Since then the car also cannot sit for more than 48hrs without draining the battery totally. It’s a 1.5 year old battery. Dealing with this for the past couple weeks unsure where to even start.

 

You might want to get a new battery and then put a battery tender on it so it's always hot. We've done that with a lot of cars.

 

You should charge and load test the battery. Even though it appears to take a charge it may be a goner. Low battery will wreak havoc with electronics and manifest it it all kinds of strange ways.

 

So true! Cars have a lot of electronics and if they aren't getting enough power, it seems to mess with everything.