Case 75XT S.N- JAF0379906 IF any one could help me with a wiring diagram for the parking brake circuit would be great. Parking brake fuse keeps blowing. While inspecting the harness I found a diode in the wiring harness below the fuse panel getting hot and smoking before the fuse blows. I removed this diode and not the parking brake works and doesn't blow the fuse. Just to clarify also I'm not taking about the resistor mounted near the fuse panel, their is a diode in the harness below that.
I figured this out if anyone has this issue. The diode is in the positive circuit for the loader valve solenoids. If that diode goes bad it is not needed just put a jumper wire in its place. The loader valve solenoid is what was causing the fuse to blow and what caused the diode to fail.
There must be a logical reason for the manufacturer to put a diode in circuit. So eventually you discovered the solenoid being defective. I'd replace the diode and see what happens. It must be there for protection of some sort. A diode only allows the flow of electrons in on direction. My guess is, without it, something is being back fed with power when it shouldn't be.
Manufacturers put the diodes in for the occasional spike back from a collapsing coil that can re-energize a solenoid. That is what I recall is the reason for them. I have installed multiple relay set ups with out having the diodes, but in pure safety terms it might be better with them. Simon C