Not saying this is your problem, but any time I find a weird 12v
problem, I look for a bad ground. If some other device, possibly way on the other side of your unit, has a bad ground, it can sometimes find the ground it needs by going through another device, such as a tail light.
First thing I would do is check battery connections. Make sure they are clean and tight. Then the other end of the ground wire.
Then, assuming the phantom lights are still lit, start pulling one 12v
fuse at a time to see if the phantom lights go out. If so, you will know which circuit needs further investigation. It could be something silly like the refrigerator control circuit. Check all the grounds associated with that circuit.