TextBox , Text value not showing?

My question is how do you get a TextValue to appear in the Textbox?

A simple example of my question is, Why does this block of code not change the Textvalue?

local TextBox = game.StarterGui.ScreenGui.TextBox
wait(10)
TextBox.Text = "No work, send halp" 

This is the piece of code I'm working with

local TextValue = game.Lighting.IntValue
local TextBox = game.StarterGui.ScreenGui.TextBox
local player = game.Players.LocalPlayer

if true then
    TextBox.Text = (TextValue.Value .. " " .. TextBox.Text .. " ".. player.Name)
    else
    TextBox.Text = ("IDK")
end