PointLight is not a valid member of Part?

I am trying to make a light on and light off script but I can't remember how to make it so the script waits for the light to be created.

lightOn = false
SmoothBlockModel = script.Parent

function onClicked()
	if lightOn == false then
		local l = Instance.new("PointLight")
		l.Brightness = 4
		l.Range = 5
		l.Parent = script.Parent
		lightOn = true
	end
	if lightOn == true then
		 script.Parent.PointLight:Destroy()
		
	end
	
	
end

script.Parent.ClickDetector.MouseClick:connect(onClicked)

lightOn = false
SmoothBlockModel = game.Workspace.SmoothBlockModel--for more effectiveness

function onClicked()
    if lightOn == false then
        local l = Instance.new("PointLight")
        l.Brightness = 4
        l.Range = 5
        l.Parent = SmoothBlockModel --Use your variables
        lightOn = true
    if lightOn == true then
   if SmoothBlockModel:findFirstChild("PointLight") then SmoothBlockModel.PointLight:Destroy()
end
end --Also leave all your ends together to make sure it runs all together.
end
end

SmoothBlockModel.ClickDetector.MouseClick:connect(onClicked)

If this helped which I hope it did be sure to accept it.

I'll rewrite it for you. Don't declare variables and not use them. Legomaster38 is trying to enforce his own scripting rules on to you too - don't listen to him.

local on = false
local block = script.Parent -- Make sure the script's parent actually is a block.

block.ClickDetector.MouseClick:connect(function() -- Try to minimize your functions.
	if not on then -- "not" is a quick way of saying "if variable == false"
		local pointLight = Instance.new("PointLight", block) -- We can set the parent in the same function
		pointLight.Brightness = 4
		pointLight.Range = 5
		on = true
	elseif on then -- Get rid of not and it means "if variable == true"
		if block:FindFirstChild("PointLight") then -- If a PointLight exists in the block
			block.PointLight:Destroy()
		end
	end
end)