Ford 8160 Electrical problems

I bought this tractor used, runs great and I bought it knowing it had lots of electrical problems. Nothing except the starter works. The PTO is stuck engaged, none of the gauges work, radio doesn"t work, climate control for the cab doesn"t work, trans wont shift at all. I mean nothing works. Sometimes the dash springs to life and the man I bought it from said one night all the lights came on and horn started blowing and it woke him up and he had to go disconnect the battery. He said one day it just lost everything and that has been a few years ago. I have all the manuals and wiring diagrams from New Holland for this tractor and I saw it has an Electrical Control Module. I priced a new one at $1296.00. This is the only piece in the manual where there is no set procedure for testing it but it seems a logical thing to replace and rule out as I go looking for this electrical gremlin. Is this a part that goes bad and has anybody ever had a 8160 do this and if so how was it resolved? I could see it maybe being a wire worn of grounding out but with this many problems I just think it has to be a major component like the module.
Thanks,
Cole

If nothing works, it's not the control module, as it does not control the lights, turn signals, horn, etc. I would be studying the wiring diagram very hard, and focus on the main power feeds from the starter post to the rest of the system. It could be as simple as a blown fusible link.

Its weird because in my brief time messing with it so far the dash randomly came on and worked correctly for a while and the previous owner said once in a great while everything would start to work. My real question I guess is would the pto resort to being in gear when power is lost, because that seems unsafe to me and is the 3pt hitch electronically controlled because it does not work either. The previous owner said that when the trans did work it went for a while then stopped after going the same distance each time and would back up the same or greater of a distance then quit that and do nothing at all which is how it is now.

My guess is that the PTO would never drive a load; it is simply spinning freely because the brake doesn't work either.

Check the wires at the ignition switch or column.

I would remove all the grounds and clean to bare metal with emery cloth and apply dielectric grease to them. If the wiring harness uses the round AMP CPC connectors make sure the blades and sockets are making good contact. Use electrical contact cleaner to get the dirt out. If you still have the same problems then check the wiring harness for rub through somewhere.

The neighbors TW 35 was acting up with electrical gremlins and it ended up being the CPC contacts in the connectors under the hood where you would split the tractor. The sockets were stretched from vibration and would not make decent contact to the blades. I bent them in with a thin blade screwdriver to tighten them up. This was 2 years ago and its still working. These can be replaced also as AMP (tyco) sells an extraction tool and replacement contacts available from Mouser or Digikey.

If your harness uses a large blue rectangular connector those are Positronics connectors. They are junk in my experience and check those for problems also. I noticed our 8970 uses them and I cringed when I saw them......

I am with jbirnsch on this. The FWA on my 8240 was engaging itself. I found out from the dealer what connection went to it. I simply pulled the connector apart then pushed it back together and it has been good. Since yours has so many problems at the same time, it would point to one of the splitting plugs, as jbirnsch indicated, either under the hood or on the side of the transmission.

Im going to pick up the tractor with a lowboy this weekend and
bring it back to my place. I think Ill check in the diagrams to find
where the splitting plugs are exactly and check it before I load it up.
It sure would be nice if I could drive it up on the trailer. A plug
makes sense because the previous owner said it was after being
transported a long way on a trailer that it stopped working and
maybe the road bumps jarred the plug loose. At least I hope its
something easy.
Thanks,
Cole