Are you sure it's the shore power light? The real shore power light was powered by a separate circuit in the old Univolt, so if you didn't make other arrangements (like using a wall-plug type 12V
transformer) to power it, it should be dark.
The other light, one that is usually in the back and mounted outside of the shell, is the 110V polarity light. If that light is on, either your power umbilical is wired backwards or the shore power connector is backwards. This is very dangerous if the shore power connector doesn't have a good ground, since the polarity light acutally makes the shell hot in this case.