Just want to make sure you understand......if the PTO light is on,your starter will not engage. I'm not sure you need a new starter at this point.
I removed the starter and tried it straight to a new fully charged battery and grounded with cables. Did same thing extended but does not spin. I have check all switches and the one that troubles me is the mid pto. It has four wire 2 green and 2 yellow. When i test it it the 2 green wires show closed when the lever is engaged. I can engage it and its open. So i assume it is working properly.