I looked at your attachments and the one for the 10,etc HP is for 72 and newer tractors. The other one does not even show the PTO. Just out of curiosity, how many spots do you have on the back of the PTO switch for wires to hook in?
I believe on the back of the switch itself there are to stems with wires connected to them. I honestly have no idea where the wire from the PTO engaged light needs to connect. Obviously to the switch I would think since the light is supposed to come on when the PTO is engaged.
I should have taken a picture of it while I was working on it. But I got it to work by just connecting disconnecting wires etc. A wire had come disconnected and I plugged it back in and tada.
I'll take some pictures next time I am under there and get some good photos posted. I want to get it wired up right so the light works.