To communicate between actors, say from a light switch actor to the light, or set of lights, you can do something like this:
Create a “LightID/DoorID” INT variable for the the actors, in this case a Door with a remote switch. Do this on both actors and set them to “Instance Editable” Under the details panel. This makes it easy to set the ID
Then enable input when the player pawn overlaps the collision volume. You can cast directly to the instance of the actor, but afaik this creates a hard reference in memory. Tags and Interfaces can be used as an alternative to checking which actor actually overlapped.
Iterate through all Lights/Doors to find the Actor Instance with matching IDs.
This is the Blueprint Interface Message Function call, from the Light Switch/Door Button.
And the Interface Event (“Receiver”) on the Light/Door.
BPI’s are available in the content browser under right-click → Blueprints → Blueprint Interface. Make sure you set an input for the variable that you’re trying to pass.