520H totally dead

[Raposo 530]

Hey guys just picked up my first 520H and boy oh boy is this thing different than my other horses! 
 

anyway, the guy I bought it from said it “wouldn’t start, and loses spark”. Got it home and started looking it over and went to turn it over and she was totally dead, no click, noises, buzzes, nada. Totally dead. Any idea where I should start? My first thought was ignition switch, but maybe it’s a safety switch? Any other switches other than seat, brake and neutral? 
 

what do you guys think? 

[ZXT 2,401]

Is there a battery in it? 

Have you checked fuses? If not, that's where I'd start. 

 

I want to say that there's a "kill" relay on the newer tractors? Could have something to do with it.

Someone more knowledgeable than me will be along shortly I'm sure!

Edited December 15, 2020 by ZXT

[Raposo 530]

It sure feels like there isn’t a battery!! Haha!

 

I charged the battery when I got it home and that seems fine. The three fuses under the hood are fine. Any others I should be checking? 

[Darb1964 1,044]

There is a thirty amp down by the starter

[lynnmor 7,317]

2 hours ago, Darb1964 said:

There is a thirty amp down by the starter

Only the early 520's had the fuse down there.

 

You should download the Demystification Guide and start with one system to troubleshoot.  The starter circuit is a bit complicated but with the help of the guide, you can start at the battery and go on till you find where the voltage is lost.  Your tractor has lights on the dash that can help you determine which safety switch is open, but you mentioned that everything is dead so maybe there is no voltage past the ignition switch.

[gwest_ca-(File Mod) 11,069]

Have a model and serial number off the data decal under the left side of the seat?

Is the wide banner decal down the side of the hood red or black?

[squonk 41,171]

9 pin molex connector near the fuse box. Check that first

[ebinmaine 67,760]

6 hours ago, Raposo said:

Any idea where I should start?

Do more testing before you replace anything. 

 

 

I can't contribute any ideas on the newer models but I'll be looking forward to seeing what you come up with...

 

 

[Raposo 530]

The machine was painted over and it looks like the plates were removed. No sure on serial number unfortunately. It’s got toro black decals. Here’s a pic

 

 

[gwest_ca-(File Mod) 11,069]

Black decals are 1990 and newer.

1990

1991-1997

Garry

[953 nut 55,389]

[Jeff-C175 7,202]

Looks like an awful lot of crud on that fuse block. I'd start by cleaning that up.  I bet there's corrosion on the terminals.  Based on the look of that fuse block my guess is that you're gonna find  more corroded connections.

[953 nut 55,389]

Any wiring connection near the battery is subject to more corrosion due to battery acid fumes over the years. If you don't clean and tighten ALL electrical connectors you will be plagued with electrical problems until you do it right.           

[lynnmor 7,317]

Your fuse block should be populated front to back as follows: Empty, 15 AMP, 25 AMP, 30 AMP.

Not saying this is the problem, but it will be after a heavy electrical load.

Let us know what you are testing and the results.

[Handy Don 12,277]

11 hours ago, Raposo said:

Hey guys just picked up my first 520H and boy oh boy is this thing different than my other horses! 
 

anyway, the guy I bought it from said it “wouldn’t start, and loses spark”. Got it home and started looking it over and went to turn it over and she was totally dead, no click, noises, buzzes, nada. Totally dead. Any idea where I should start? My first thought was ignition switch, but maybe it’s a safety switch? Any other switches other than seat, brake and neutral? 
 

what do you guys think? 

Hello Raposo. I was hoping a member would grab that 520-H from the Hartford CL. The price was good, for sure. I saw the listing an hour after it was posted and seriously though of hitching the trailer and going for it.

I've just spent a lot of time with the wiring on a similar vintage 520 and cannot overemphasize that on a unit as old as that you should not trust ANY of the connections until you've checked them--fuses, grounds, gauges, etc. The demystification guide is essential and, frankly, skipping steps will just cause you frustration. Take the time and go through one by one. Do not remove more than one connection at a time, check for resistance (ohmmeter), clean it and put it back with dielectric grease, recheck resistance.  Do not completely trust the colors of the wires--the wiring diagram's colors were aspirational, the routing is gospel! Do not take off a bunch of connections thinking you'll remember how they go back. Plan on hours, not minutes. The odds are you have at least five and maybe even fifteen bad or weak connections. With patience, you'll likely end up with a very solid machine. Good luck.

[SPINJIM 1,981]

There is also the PTO lever kill-switch.   From the looks of the fuse block, I'd say you probably have a few corroded connections.  I'd start by cleaning all of the connections, and (as Squonk said) check the 9-pin connector for a burnt connection.  There are also a few in-line fuses.  Get the wiring diagram for something like a 1992 model, and trace the circuits.   A continuity tester will help.

   Good luck, Jim

[R Scheer 502]

Don't forget the ground connections.  If it was repainted they may not have cleaned the paint off before connecting the grounds, poor ground and it will act like there's no battery.

[roadapples 6,983]

Hold the key on and wiggle the fuse wires...

[Handy Don 12,277]

2 hours ago, R Scheer said:

 

Don't forget the ground connections.  If it was repainted they may not have cleaned the paint off before connecting the grounds, poor ground and it will act like there's no battery.

 

Repainted the blower cover and the voltage regulator lost its ground. Engine started and ran great but lights were dim and the battery would not charge! Wired a separate ground to the screw that holds it and voila!

[Horse Newbie 7,081]

On 12/15/2020 at 7:37 AM, 953 nut said:

electrical problems

 

On 12/15/2020 at 7:37 AM, 953 nut said:

If you don't clean and tighten ALL electrical connectors you will be plagued with electrical problems until you do it right.     

I checked, cleaned, and di-eletric greased all my connections... Gauges, terminal ends, and bypassed the 9 pin molex connector on the start and charge circuit on my 1994 520 H and it made a big difference..plus gave me a little peace of mind.

Edited December 27, 2020 by Horse Newbie

[Bob Reed 2]

On 12/14/2020 at 10:20 PM, Raposo said:

Hey guys just picked up my first 520H and boy oh boy is this thing different than my other horses! 
 

anyway, the guy I bought it from said it “wouldn’t start, and loses spark”. Got it home and started looking it over and went to turn it over and she was totally dead, no click, noises, buzzes, nada. Totally dead. Any idea where I should start? My first thought was ignition switch, but maybe it’s a safety switch? Any other switches other than seat, brake and neutral? 
 

what do you guys think? 

I had the same issue with my 1991 520H.  Ran great then just died.  By the time I got done, I replaced the oil temp sensor, coils, wires and plugs, internal ignition coil ( which isn't too bad on the onans) and bypassed the fuse block with individual fuses.  I also had to replace the splice block on the harness.  Finally no power to the ignition switch ( which I replaced too).  Had to jump power to the coil packs and it runs great.  Only issue now is the engine temp light is on, but it ran 4 hrs and no overheating.  For an old machine, it was worth it. 

[Bob Reed 2]

Just now, Bob Reed said:

I had the same issue with my 1991 520H.  Ran great then just died.  By the time I got done, I replaced the oil temp sensor, coils, wires and plugs, internal ignition coil ( which isn't too bad on the onans) and bypassed the fuse block with individual fuses.  I also had to replace the splice block on the harness.  Finally no power to the ignition switch ( which I replaced too).  Had to jump power to the coil packs and it runs great.  Only issue now is the engine temp light is on, but it ran 4 hrs and no overheating.  For an old machine, it was worth it. 

Oh, and replaced 2 safety switches which turns out weren't bad, but saved a step in the future.  About 300 in parts and a few days labor.  Hint, I would start with the white connector in the wiring harness.  If the contacts look burnt, replace it, but be careful to put the right wires in the right spots.  Then check the internal ignition coil.  That was my main problem.