John Deere 4520 model 05. Has kit added by JD to add SCV’s 4 and 5 to the rear. The switch is located on the right panel, next to the lift handle, not on the joystick or on the fender.
The switch is on the right panel next to the lift handle not on the joystick or the fender. The loader should not move when the switch is activated.
The problem is that my loader keeps lowering, and nothing that is connected to the rear controls “SCV 4 and 5” works.
The loader lowers, but has no lowering pressure which means it falls but wants to pick up the tractor.
I took the solenoid bypass coil and stem to the hydraulic shop and they said it is working fine.
It appears that the solenoid valves are not working. The valves were stuck from lack of use. There could be a blown fuse causing the problem, so that would be the first thing to check.
Then I would check that there is voltage on each of the solenoid valves. Put the switch in the normal position and see which solenoids are live. Flip the switch and check the voltage across each solenoid.
In the normal position, two of the solenoids should be energized and the two opposite solenoids should be energized. Operate the switch and the opposing solenoids must be live and the other two solenoids must be de-energized.
If the valves are stressed but not working, the valve spools could be frozen. I would first try to hit the valve body with a hammer and flip the switch. If nothing happens, the next step would be to remove the solenoids and see if you can move the reels.
This is how I would attack this problem.