I just found some more examples here and this one does work to turn on a “Switch”
require "core"
local items = core.get_items()
if items then
for _, item in ipairs(items) do
if item.name == "switch" and item.device_id == "<Device-ID-Here>" then
core.set_item_value(item.id, true)
end
end
end
You have to use the device ID not the item ID of the switch component of that device.