520H won't start

[BlueOx 4]

Hi all, I recently was given a 520H for doing some service work for a guy. other than the seat being cracked it's in pretty good shape. the model is 73501. I charged the battery back up(been sitting a long time) and it fired up! cranking and shutting off a couple times to check everything out. I noticed with the hood up that the front fuse slot had a jumper wire in it. it appeared that this position had issues before cause the fuse holding part was pretty burned up. I could wiggle the jumper and the starter would work so I replaced the wire with a fuse and dielectric grease. I still had to wiggle the fuse to get a connection for a start but then it stopped working altogether. I took the fuse block loose and inspected underneath and it was some burned up so, I cut the 3 wires on the front fuse (one red and 2 white) and used spade females to input a fuse bypassing the block altogether. then I noticed that the next fuse back had a jumper rail that fed to the front fuse. I tried jumping those and still no crank sequence. I can hear a clicking under the battery tray that sound like maybe a relay not working right. I'm confused cause in the beginning it would crank when wiggiling the front fuse but with that work around I get nothing. trying to figure out how to get underneath the battery tray without having to dismantle the whole dash assembly.

anyone run into an issue like this before? I don't get any voltage to the starter solenoid . any  help would be greatly appreciated since I've cranked and driven it around some and it's a nice unit.

[lynnmor 6,762]

Replace the fuse block with a Dorman 85668.

 

The relays normally give a slight click, they are best accessed by removing the belt cover on the right side.

 

The seat safety switch, ignition switch and the PTO switch may have an issue.  Use the Demystification Guide to troubleshoot each system.

 

There is a white 9 pin connector near the battery, they are known to fail.

 

Make sure that the old battery is OK, it can be tested for free at most auto parts stores.

[peter lena 8,038]

  @BlueOx agree with @lynnmor  on that fuse block replacement , another glairing wiring issue on the 520,s  is wire stress and chafing in its original set up , very often the plug in connection portals are stress cracked and have a powdery electric cracking tracking / shorting point . have any small alligator wire clip connectors ?  often use those to compete a run . your electrical clicking is good and means you are close . look for any fried wires and  jump a connection to run . then you can plan your replacement . another thing when rewiring , change those tight wire, chaffing  wraps , use a cable wrap to protect as you go . good luck with it , pete

[Chuck14025 9]

I tried fixing all the connections, finally found major problems with the inaccessible safety circuit breakers in front of the battery. I wired a bypass to the starter solenoid, started 'er up and moved on. I closed the circuit on some of the breakers, the seat for one.   It's a great tractor and worth the effort.

[Handy Don 10,567]

19 minutes ago, Chuck14025 said:

I tried fixing all the connections, finally found major problems with the inaccessible safety circuit breakers in front of the battery. I wired a bypass to the starter solenoid, started 'er up and moved on. I closed the circuit on some of the breakers, the seat for one.   It's a great tractor and worth the effort.

I hope now that its running you'll go back and, one by one, replace the faulty safety switches. A great tractor is worth the effort to be safe for its operators and anyone nearby.