Electronics

You added a lot there I hadn’t thought about. But that said....

12v won’t hurt it, but it will engage at about 9v

Does anyone know the proper voltage to the front final drive to engage?  I was thinking of testing it but sometimes these things only use smaller voltages. Don't want to burn up anything.

Previous repairs check good, 4WD switch tested good. Going spend the day with a multimeter after I get baxk from checking the hog traps and picking a couple barrels of corn

Lol all we had was the green stuff, chcks and western union—gawd were they proud of themselves.   i missed out on buying the remains of an 87 350D for $52. I’m a little bummed about it but it was in worse condition than your quest. We’re both better off eh?