How do I fix this repeat to make the desiredangle go down and up after the before code?

So, I am trying to make this script randomise a motor6d start position, then go either down or up and then just keep going down and up. It works fine until the repeat. It goes to StartPosition and moves to DesiredPosition and then go the other way but then it stop and won't keep going up/down.

I tried this at first:

local tilt = script.Parent.Startposition.Value
	 
	function OnClick(Player)
	        script.Parent.Startposition.Value = math.random(-15,15)/10
	        script.Parent.Desiredposition.Value = math.random(0,4)
	        wait (0.5)
	        script.Parent.Tilt.CurrentAngle = script.Parent.Startposition.Value
	        wait (0.05)
	        script.Parent.Tilt.DesiredAngle = script.Parent.Startposition.Value
	        wait (0.05)
	        if script.Parent.Desiredposition.Value >= 3 then
	        script.Parent.Tilt.DesiredAngle = 1.5
	        script.Parent.Direction.Value = 1.5
	        else
	        script.Parent.Tilt.DesiredAngle = -1.5
	        script.Parent.Direction.Value = -1.5
	        end
	        repeat wait(0.1) until script.Parent.Tilt.CurrentAngle == script.Parent.Direction.Value
	    print ("weee")
--- I think this below is what won't work
	    repeat
	        if script.Parent.Direction.Value == 1.5 then
	        script.Parent.Tilt.DesiredAngle = -1.5
	        else
	        script.Parent.Tilt.DesiredAngle = 1.5
	        end
	        repeat wait(0.1) until script.Parent.Tilt.CurrentAngle == script.Parent.Tilt.DesiredAngle
	    until
	    script.Parent.On.Value == false
	 
	end
	 
	
	
	game.Workspace.TES2.ClickDetector.MouseClick:connect(OnClick)

Did not output any errors and still did not work so I tried changing the repeat to another thing but still did not work better.

	print ("weee")
	repeat
		if script.Parent.Tilt.DesiredAngle == 1.5 then
		script.Parent.Tilt.DesiredAngle = -1.5
		else
		script.Parent.Tilt.DesiredAngle = 1.5
		end
	repeat 
	wait(0.1) 
	until 
	script.Parent.Tilt.CurrentAngle == script.Parent.Tilt.DesiredAngle
	until
	script.Parent.On.Value == false
		
		

end

All help appreciated.

[ EDIT BELOW ] I tried switching to this too. Still no errors and still won't work.

	print ("weee")
	repeat
		if script.Parent.Tilt.DesiredAngle == 1.5 then
		script.Parent.Tilt.DesiredAngle = -1.5
		else
		script.Parent.Tilt.DesiredAngle = 1.5
		repeat wait(0.1) until script.Parent.Tilt.CurrentAngle == script.Parent.Tilt.DesiredAngle
		end
		until script.Parent.On.Value == false
		

end