no power to head lights cab lights ignition or steering column the battery has 12-4 volts coming out of it. tried jumping with another car and nothing happened.
I would first check that both sides of the battery cables are free of corrosion and connected correctly. Take a good look at the ground cable. Also when you say the battery is putting out 12.4v you should check if that is the same when you put your test-leads one on the positive battery post and the other on a frame screw or the engine. That should give you a better idea if there is an issue with battery ground. The next thing to check would be the fuses. Especially if there is a master fuse on the battery cable.