You can create two triggers that are both required for the action to occur - one that requires the player to stand in close proximity to the switch (area trigger) and another that requires the player to hit it (i.e. press a button). This will require character to move their character next to a switch and 'use' it.

Set up your object that requires the player or ally to hit it so that it may trigger an event but have the script for this event disabled from the start by attaching the 'Toggle Element' script node set to disabled and have a second script node set up as an 'Area Trigger' so that when a player or ally steps into the area it toggles the original script on.