Tear the trim from the rear area and get to the CLP/SSM. Unplug every connector and look for water intrusion and corrosion. Water damage to the CLP/SSM is common in Roadsters and way less common but not unheard of in Coupes. Damage that water causes will cause many of your symptoms (wing issues, lights that stay on, battery drains on it's own....) I would look at that first.

No, I"ve never owned a coupe and don't know how to get to it in the coupe but I've replaced several CLP/SSMs in Roadsters with this issue.

IF you find water damage, you need a CLP/SSM from a 'donor car', they require no programming and all CLP/SSMs in Coupes, Roadsters, SRT6s, etc - are the same. Also, get the last 2-3 feet of wiring harness as you can not clean the pins of the connectors once they are corroded.

IF you find no damage, you can move on to other suspects.