520H Completely Dead

[bds1984 1,395]

So here goes the story.  My 520H just rolled over 700 hours today after mowing.  No issues to speak of, just a typical seat time.  Afterwards, I shut the machine down so I can clean her off before parking her back in the garage.  However, after shut down and cleaning, I turn the key and everything is dead; no warning lights, no clicks, no voltage at the meter.  Odd, so I check the fuse box that looks a little suspect and with the key OFF I have almost 13 volts at both 25 amp fuses going in and out and nothing at the 15 amp fuse.  Odd.  With the key on there is nothing at all three, everything is dead.  This makes zero sense.  I go to check other points on the circuitry and have the same 13 volts at the voltage regulator with the ignition switch off and nothing when the key is turned on.  Since this is my first complete and running 520, I immediately went for the 9-pin connector to inspect for crustiness and nothing.  It is clean, although a little dusty from years of use, but no evidence of poor electrical connection that I've heard many here experience.  
Am I wrong in assuming the ignition switch has flaked out internally?  I am leaning towards replacing that but unfortunately I'd have to wait a few days for a replacement.  Any suggestions?

[Pullstart 60,087]

Brandon, could you pull the switch out and still have it hooked up and troubleshoot with a meter, or just use the meter to troubleshoot the switch?  Should be able to watch continuity run through tabs at various positions..

[bds1984 1,395]

I tested the switch's continuity unhooked and hooked up to the tractor and it made zero difference. For S&G I used a jumper from the power terminal to the other three only to get the safety lights to blink, dash lights to light up, and clicking beneath the battery. A second attempt couldn't replicate anything. This thing has  Lucas electrical components in it for sure. 

[varosd 1,185]

Sucks!

I miss my Onans!

anyway, What year are is your tractor?

pictures please 

[roadapples 6,981]

I'm not much of an electrician. When I got mine sometimes it would not start. I would hold the key on and wiggle the fuse wires. Replaced all with in line fuse holders with caps soldered and shrink tubed. No more problems...

[953 nut 52,162]

Like Jay @roadapples said, take the time to fix it right and it will pay off. There are probably several opportunities to improve your wiring and correct the problem as you go along. Voltage disappearing tells me there are connectors that have enough corrosion that they will not carry a load.

Not too sure what year your 520 is so I chose the 1988-1989 drawings. Use these diagrams as a guide.

 

Edited August 12, 2022 by 953 nut

[bds1984 1,395]

It's a 1995. I knew at some point I'd have to replace the fuse block, I guess I'll dig into that and any electrical connections soon. Something is telling me that since the seat and pto safety switches didn't function, I am going to unravel what the previous owner did and hopefully get this rig back and running. I greatly prefer mowing with a hydro.

[squonk 39,121]

Probably the 9 pin connector

[953 nut 52,162]

8 hours ago, bds1984 said:

1995

 

[bds1984 1,395]

I finally had some time to take inspect the wiring on this rig and am embarrassed at what I found. The wire on the starter solenoid was loose. That's it. Total noob mistake. However I did find the 9-pin connector looks good but the fuse block is crispy on the foremost fuse. That'll be a project for later today.