Changing Ambient setting for different sections of the same game?

local player = game.Players.LocalPlayer

player.CharacterAdded:connect(function(character)) character:WaitForChild("Left leg") character:WaitForChild("Right leg")

for _, limb in pairs(character:GetChildren()) do
    if limb:IsA("BasePart") then
        limb.Touched:connect(function(otherPart)
            if otherPart.Name == "Trigger" then
                game.Lighting.Ambient = Color3.new(
                    math.random(0, 255)/255,
                    math.random(100, 150)/255,
                    math.random(200, 255)/255
                )
            end
        end)
    end
end

end)

Walking on the trigger doesn't seem to activate the script!