After a road test with the right rear lamp unplugged all my problems seem to go away. Turning the headlights on does not disable the cruise control anymore. I can take the key out of the ignition with the headlights on and the brake pedal pressed and the car actually turns off. I'm gonna check the wiring harnesses tomorrow. The issue has to be coming from the rear stop lamp wiring. Disconnecting it gets rid of all the problems I've been having.