JCB 512 56 issue

[JellyBean]

Man, I bought this used JCB 512 56 a few months ago, now I'm trying to fix the wiring harness fire and it's a real puzzle.

Looks like someone bypassed everything that wasn't for the steering. From what I can tell, the only juice flowing through this harness was to the four solenoids and two proximity sensors, plus a couple of lines heading to the fuel tank (guessing for the pump and gauge).
The kicker is, the wires for the solenoids on the second valve are totally fried.

Now I've got two wires where I only need one, and three where I need two. How in the world do I figure out which is which?
I'm hoping to fix this thing at home, but I might have to drag it onsite if I can't sort this out.

Any ideas on how to tell these wires apart?

 

[d0ugg.348]

Man, I bought this used JCB 512 56 a few months ago, now I'm trying to fix the wiring harness fire and it's a real puzzle.

Looks like someone bypassed everything that wasn't for the steering. From what I can tell, the only juice flowing through this harness was to the four solenoids and two proximity sensors, plus a couple of lines heading to the fuel tank (guessing for the pump and gauge).
The kicker is, the wires for the solenoids on the second valve are totally fried.

Now I've got two wires where I only need one, and three where I need two. How in the world do I figure out which is which?
I'm hoping to fix this thing at home, but I might have to drag it onsite if I can't sort this out.

Any ideas on how to tell these wires apart?

I hear you.. it's always a puzzle when you're dealing with someone else's fixes! What you described seems to be the boom extension and crowd solenoids, which are usually a common point of failure. But this should be easy to sort out without hauling it in to a shop.. just use a multimeter and set it to the continuity function. Start tracing the wires from the connectors at the solenoids back into the main harness. Even if they're burned, you might be able to find a bit of the original color near the connector or where the harness was less exposed. The three wires where you need two are likely two separate solenoids that share a common power wire. Also check for continuity between the three wires and a known power source on the machine like the ignition switch or fuse box. The one that has continuity with the power source is your main power wire, and the other two are your switched wires. A wiring diagram for the JCB 512-56 would be a huge help here if you can find one!

 

[yellowbeastPil0t]

Totally agree. Using a multimeter for continuity testing is spot on for figuring out the function of each wire. You made a great observation about checking the original wire colors in protected areas, heat damage typically doesn't extend past the harness entry points. That tip about checking the power source continuity is sure to help quickly pinpoint the common wire

 

[autoclave_44]

I hear you.. it's always a puzzle when you're dealing with someone else's fixes! What you described seems to be the boom extension and crowd solenoids, which are usually a common point of failure. But this should be easy to sort out without hauling it in to a shop.. just use a multimeter and set it to the continuity function. Start tracing the wires from the connectors at the solenoids back into the main harness. Even if they're burned, you might be able to find a bit of the original color near the connector or where the harness was less exposed. The three wires where you need two are likely two separate solenoids that share a common power wire. Also check for continuity between the three wires and a known power source on the machine like the ignition switch or fuse box. The one that has continuity with the power source is your main power wire, and the other two are your switched wires. A wiring diagram for the JCB 512-56 would be a huge help here if you can find one!

Really helpful, thanks! I just picked up a used 512-56 for orchard work. The wiring's a mess from past repairs, so I'm trying to sort it out myself. When checking continuity, do you test with the key on or off? Also, any tips for finding a clean wiring diagram? Seen a few online but not sure which ones are legit.