I hit a tree root with my Scotts Tractor and now connot engage the blades. The pulleys and shafts appear OK. I believe the cause is in the wiring. Where can I get a copy of the wiring diagram for this tractor? Or... does someone have an alternate diagnosis?

Have you checked the belts first? Blades are never direct driven. They can snap pretty quick if the blades get stopped by an object.

This is made by John Deere.

http://jdpc.deere.com/jdpc/servlet/com.deere.u90490.partscatalog.view.servlets.HomePa geServlet_Alt

User manual

http://dl.owneriq.net/7/74d6465d-604f-df44-71f6-2ff6ec9f391a.pdf

Link to buy the service manual from John Deer for $29.00

http://www.deeretractors.net/store/products/john-deere-scotts-s2554-lawn-and-garden-tractor-service-manual-download/

I looked for but couldn't find a free copy on the internet.

I checked the belts. I then removed belts and checked for loose tolerance of shafts... none detected. Replaced belts. Belts and pulleys move freely manually. No wiring diagram available in Owner Manual. Charged battery (suggested) and tried Blade switch w/ key is on position... magnets kicked in as expected.. No luck. Appears to be in clutch wiring?

Hi,
I agree! Check the clutch wires just inside the fram on the right side of the machine.
Peace,
Clarke