520 electrical gremlins

[huey 7]

My 520h i'm unsure of the year as no numbers on the seat pan, but it does have the foward swept axle and gear reduction. 

The problem i'm having is i can't get power to the starter solenoid. i have cleaned the ground wires beside the battery and the ground to the engine, also checked the 9 pin connection(both sides) and removed the fuse block and cleaned it up. also did a continuity test on the light blue wire from the solenoid to the re-lay block and is good.also tested the re-lays and all in working order.  i have checked the micro switches and all working except for the seat switch i have jumped the orange to the brown but when i try to turn over the seat switch light comes on in the dash and prevents from turning over. just looking for more suggestions!

[Handy Don 12,233]

26 minutes ago, huey said:

My 520h i'm unsure of the year as no numbers on the seat pan, but it does have the foward swept axle and gear reduction. 

The problem i'm having is i can't get power to the starter solenoid. i have cleaned the ground wires beside the battery and the ground to the engine, also checked the 9 pin connection(both sides) and removed the fuse block and cleaned it up. also did a continuity test on the light blue wire from the solenoid to the re-lay block and is good.also tested the re-lays and all in working order.  i have checked the micro switches and all working except for the seat switch i have jumped the orange to the brown but when i try to turn over the seat switch light comes on in the dash and prevents from turning over. just looking for more suggestions!

The usual suspects for power not activating the solenoid are the PTO switch and the Neutral switch. These govern the "auxiliary" relay that activates the starter solenoid. PTO must be disengaged. Motion control must be in neutral. Check these microswitches and their connections.

Do you have the wiring diagram? The Demystify document?

Search the files section of this site for them e.g. "demystify" and "tractor 520-H" (be sure to choose "files" or "documents" as the place to search and choose "use all my search terms")

 

[huey 7]

21 minutes ago, Handy Don said:

 

 

 

Edited September 19, 2022 by huey

[huey 7]

Thanks Handy Don, i will check them again. When i tested them with a test light they each had power going to each switch and when i would engage the pto or the neutral the micro switches would switch power to the other wire on the switches but maybe ones sticking somewhere

 

[Handy Don 12,233]

5 minutes ago, huey said:

Thanks Handy Don, i will check them again. When i tested them with a test light they each had power going to each switch and when i would engage the pto or the neutral the micro switches would switch power to the other wire on the switches but maybe ones sticking somewhere

 

Ah, didn't mean to insult you. "Checked" has a wide variety of meanings from many folks who post here.

In your case, I'd be tempted to put the tractor in neutral, chock the wheels, and then use a jumper direct from the positive terminal of the battery and try touching it first to the starter solenoid input and if that works, then to the "auxiliary relay" input. If THAT works, then you know those two components are good and you've got a wiring or switch glitch. Get the demystify doc and work backward from there.

Edited September 19, 2022 by Handy Don

[gwest_ca-(File Mod) 11,046]

These wiring diagrams are from the 523 page Demystification Guide.

Each major circuit has it's own diagram and that simplifies diagnosis but you need to download the file to get them.

I do not know the difference between 1990 and 1991-97.

Click on the picture in each link and the page that comes up can be enlarged for a preview.

Pretty sure 1990 and newer had the special front axle.

The starter diagram shows what needs to happen for it to work.

 

 

[953 nut 55,290]

11 hours ago, huey said:

i have checked the micro switches and all working except for the seat switch i have jumped the orange to the brown but when i try to turn over the seat switch light comes on in the dash and prevents from turning over. just looking for more suggestions

The seat switch is not a part of the START system on the 1990 model but is on the 1991 and newer. @Handy Don's suggestions are a good start (no pun intended). I would also suggest manipulating the PTO lever slightly while attempting to start the engine. If the PTO switch is out of adjustment or just being finicky that sometimes prevents the start signal from being passed.

Here are the two drawings of start systems, hope this helps.

 

[huey 7]

Ok i have checked the pto and neutral switches and are working properly. When i turn key on i have power to +coil  so  kill relay is working properly i think. When i check the switch relay block there is power to orange wire without relay plugged in and i get power to the tan coloured wire when i turn ignition switch to start without the relay plugged in which is probably a direct wire from the key switch  when i check the start relay without the relay plugged in i have power to a white wire. When i plug in all relays i can't seem to get the switch relay to send power to the start relay to send power to the solenoid? On another note i did jump a power wire directly to the solenoid and it started but would like to fix properly.

[953 nut 55,290]

The inputs to both relays seem normal. The Tan wire being energized with the ignition switch in START should cause the switching relay to close. Place your finger on the top of the switching relay and see if you can feel/hear the switching relay closing when the key is turned to START. If the switching relay is not closing then put the kill relay in it's place and repeat. (all three relays have the same part number) If the kill relay works then see if the start relay also works. If they both work you will just need a new five pin relay that any auto parts store should have in stock for $ 10 or less (or you can spend $ 30.00 for the same thing from Toro.

[huey 7]

29 minutes ago, 953 nut said:

The inputs to both relays seem normal. The Tan wire being energized with the ignition switch in START should cause the switching relay to close. Place your finger on the top of the switching relay and see if you can feel/hear the switching relay closing when the key is turned to START. If the switching relay is not closing then put the kill relay in it's place and repeat. (all three relays have the same part number) If the kill relay works then see if the start relay also works. If they both work you will just need a new five pin relay that any auto parts store should have in stock for $ 10 or less (or you can spend $ 30.00 for the same thing from Toro.

When I touch the switch relay or the start relay while the ignition switch is in the start position i can feel them both click, i have also switched them around with no luck. Do you think i should still buy a new one to give it a try?

[953 nut 55,290]

On 9/18/2022 at 9:30 PM, Handy Don said:

put the tractor in neutral, chock the wheels, and then use a jumper direct from the positive terminal of the battery and try touching it first to the starter solenoid input

Have you done what @Handy Don suggested putting power directly to the small terminal on the Solenoid?

 

11 hours ago, huey said:

When I touch the switch relay or the start relay while the ignition switch is in the start position i can feel them both click

If both relays are closing you should have 12 volts going to the small terminal on the solenoid, is the power getting there?

 

11 hours ago, huey said:

Do you think i should still buy a new one

If they are all working there wouldn't be any gain by replacing them, 

[huey 7]

13 minutes ago, 953 nut said:

Have you done what @Handy Don suggested putting power directly to the small terminal on the Solenoid?

 

If both relays are closing you should have 12 volts going to the small terminal on the solenoid, is the power getting there?

 

If they are all working there wouldn't be any gain by replacing them, 

When I run a direct wire to the solenoid it turns over and will start  the problem I am having is at the bottom of the switch relay there is a purple wire that jumps over to the start relay which isn't doing anything.  I have also did a continuity test on the light blue wire from the start relay block to the solenoid  and tests good

[Handy Don 12,233]

We need to be methodical and sequential here. Please answer these questions...

Reply back if you come to a NO answer.

 

Note exactly where I'm suggesting you apply power. 

Turn the ignition OFF.

If you jumper power to the light blue wire connection on the Start Relay, does the engine crank? If yes, starter solenoid is ok

If you jumper power to the dark blue wire connection on the Switching Relay, does the engine crank? If yes, start relay is ok.

If you jumper power to the tan wire connection on the Switching Relay, does the engine crank? If yes, Switching relay is ok

 

Now to @953 nut's points.

 

Turn ignition ON.

Is there 12v at the dark green wire connection to the Switching Relay?

(If no, then the problem is in the wiring, connections, or switches between here and the battery including, possibly, the ignition switch and fuse!)

 

Turn the ignition to START and hold it there

Is there still 12v at the dark green wire connection to the Switching Relay?

(If no, then there is a short circuit or the ignition switch is bad.)

Is there now 12v at the tan wire connection to the Switching Relay?

(If no, there is a bad connection between the S terminal on the ignition switch and the Switching Relay)

Edited September 20, 2022 by Handy Don

[gwest_ca-(File Mod) 11,046]

I was advised the purple wire should be changed to white - maybe that is not correct.

The purple/white wire is connected directly to the battery + so should be hot at all times.

If they made the connection at the fuse block by placing more than one wire in a terminal there is the problem.

[huey 7]

4 hours ago, Handy Don said:

We need to be methodical and sequential here. Please answer these questions...

Reply back if you come to a NO answer.

 

Note exactly where I'm suggesting you apply power. 

Turn the ignition OFF.

If you jumper power to the light blue wire connection on the Start Relay, does the engine crank? If yes, starter solenoid is ok

If you jumper power to the dark blue wire connection on the Switching Relay, does the engine crank? If yes, start relay is ok.

If you jumper power to the tan wire connection on the Switching Relay, does the engine crank? If yes, Switching relay is ok

 

Now to @953 nut's points.

 

Turn ignition ON.

Is there 12v at the dark green wire connection to the Switching Relay?

(If no, then the problem is in the wiring, connections, or switches between here and the battery including, possibly, the ignition switch and fuse!)

 

Turn the ignition to START and hold it there

Is there still 12v at the dark green wire connection to the Switching Relay?

(If no, then there is a short circuit or the ignition switch is bad.)

Is there now 12v at the tan wire connection to the Switching Relay?

(If no, there is a bad connection between the S terminal on the ignition switch and the Switching Relay)

 

Ok so the first spot i ran into a issue when applying power with ignition off is the TAN wire connection. The switching relay clicks but the engine dosen't crank so i switched relays and still only clicks what do you suggest? Next i turned ignition on and have 12v power to the dark green wire at the switching relay but when i turn the ignition to start dark green looses power. Thanks for the help! 

Edited September 20, 2022 by huey

[953 nut 55,290]

10 hours ago, huey said:

purple wire that jumps over to the start relay which isn't doing anything.

That purple wire should have 12 volts directly from the battery at all times, take a close look at it from one end to the other to find out where it has become disconnected.

1 hour ago, huey said:

turned ignition on and have 12v power to the dark green wire at the switching relay but when i turn the ignition to start dark green looses power.

That is a bit strange. Previously both the Switching and Start relays were closing, power to the green wire is needed to allow the Switching relay to energize and close the Start relay. Make sure the PTO lever hasn't moved. The other possibility is the ignition switch, part # 103990, could be marginal but I wouldn't run out and get a new one yet. 

Lets concentrate on the Purple wire for now, once it has power and the solenoid is closing properly if there is intermittent trouble with the ignition switch you can order one for about $ 16.00 ship-to-store from Wally World or on 

[huey 7]

45 minutes ago, 953 nut said:

That purple wire should have 12 volts directly from the battery at all times, take a close look at it from one end to the other to find out where it has become disconnected.

That is a bit strange. Previously both the Switching and Start relays were closing, power to the green wire is needed to allow the Switching relay to energize and close the Start relay. Make sure the PTO lever hasn't moved. The other possibility is the ignition switch, part # 103990, could be marginal but I wouldn't run out and get a new one yet. 

Lets concentrate on the Purple wire for now, once it has power and the solenoid is closing properly if there is intermittent trouble with the ignition switch you can order one for about $ 16.00 ship-to-store from Wally World or on 

Ok looking at your diagram my wire colours aren't all the same, the purple wire i was talking about shows dark blue in your diagram. ok i have the seat switch bypassed (orange to brown) joined together and i went and started the tractor with a wire from battery to solenoid just to get it running and when i put the pto foward or move the motion control lever it kills the engine so i'm pretty sure the micro switches are working.I have also tested the relays each on there own with aligator clips to positive on 85 and negative 86 and the relay clicks also a continuity test from #30 to 87 then removed power and had continuity between #30 to 87a

 

Edited September 21, 2022 by huey

[Handy Don 12,233]

5 hours ago, huey said:

 

Ok so the first spot i ran into a issue when applying power with ignition off is the TAN wire connection. The switching relay clicks but the engine dosen't crank so i switched relays and still only clicks what do you suggest? Next i turned ignition on and have 12v power to the dark green wire at the switching relay but when i turn the ignition to start dark green looses power. Thanks for the help! 

Ok, thanks for getting onto this step by step. Your work has isolated the problem.

1. Having power at the green wire with the switch ON tells you that the ALL the safety switches are ok and properly positioned. (Having the PTO lever kill the engine with the tractor running reinforces that.)

2. There are only three ways left that can cause the green wire to go dead when the tan wire gets 12v by turning the ignition switch:

a) the ignition switch is busted,(it's disconnecting the battery from the I terminal when the key rotates to the Start position) -- kinda likely

b) it is the wrong switch -- not likely unless it has been changed and the tractor has never worked properly with this switch in place

c) the switch wiring is incorrect -- this is my bet. I think the orange wire at the switch is attached to the "A" (accessory) terminal on the switch and not the "I" (ignition) terminal since that would perfectly explain the behavior you are seeing, including the weird behavior of the idiot lights (there is probably a different colored wire wire attached to the "I")

 

Please get a very clear picture of the back of the switch if you can with good light BEFORE moving any wires so that we can be very sure of how is is wired  BEFORE changing anything!

Let us know what's there!

 

Edited September 21, 2022 by Handy Don

[953 nut 55,290]

9 hours ago, Handy Don said:

b) it is the wrong switch -- not likely unless it has been changed and the tractor has never worked properly with this switch in place

c) the switch wiring is incorrect -- this is my bet. I think the orange wire at the switch is attached to the "A" (accessory) terminal on the switch and not the "I" (ignition) terminal since that would perfectly explain the behavior you are seeing, including the weird behavior of the idiot lights (there is probably a different colored wire wire attached to the "I")

Thanks @Handy Don, we never have asked about the history of this problem and the 520 itself.

Were all electrical functions working properly and then this condition just began?

Is there any evidence that the previous owner has tampered with the wiring and it was this way when you bought it?

11 hours ago, huey said:

i have the seat switch bypassed (orange to brown) joined together and i went and started the tractor with a wire from battery to solenoid just to get it running and when i put the pto foward or move the motion control lever it kills the engine so i'm pretty sure the micro switches are working.

With the seat switch bypassed the Kill relay should remain energized and continue providing power to the ignition until the key is turned off. These two drawings show the ignition system in start and run condition. The seat switch is parallel to the PTO, neutral switch and Switching relay. Any or all of these three could be open and the engine continue to run with the seat switch bypassed, the kill relay opens on a loss of power.

[Handy Don 12,233]

Assuming that the wiring is not otherwise FUBAR, then to me that the tractor runs with the switch on after being jumped to get it to crank eliminates ALL of the safety switches and their wiring as a culprits, including the kill switch relay. Everything I've understood so far points to someone taking the wires off the ignition switch (accidentally or for some purpose) and putting them back incorrectly.

 

I strongly ask and recommend though, @huey, that once it is operating properly you remove the seat switch bypass and any other safety defeats. Despite protestations of some folks, those safety devices DO save users from injury and even death. Do not take my helping you diagnose your issue as abetting operating the tractor with circumvented safety switches.

Edited September 21, 2022 by Handy Don

[gwest_ca-(File Mod) 11,046]

Start relay should be

#85 dark blue - should have power with ignition switch in start position

#30 purple - should have power at all times

#86 black ground

#87 light blue - should have power with ignition switch in start position but power coming from #30 purple

 

Conclusion - the dark blue and purple may be reversed

 

[Handy Don 12,233]

2 minutes ago, gwest_ca said:

Start relay should be

#85 dark blue - should have power with ignition switch in start position

#30 purple - should have power at all times

#86 black ground

#87 light blue - should have power with ignition switch in start position but power coming from #30 purple

 

Conclusion - the dark blue and purple may be reversed

 

Garry, I'm not familiar with the numbering you reference. Where is that documented?

[gwest_ca-(File Mod) 11,046]

Click on the pictures to enlarge

 

[Handy Don 12,233]

1 hour ago, gwest_ca said:

Conclusion - the dark blue and purple may be reversed

If these were reversed, wouldn't the Start Relay be energized at all times, regardless of ignition switch position?

In that case, simply switching the ignition switch to "On" would put power through the blue wire and energize the Start Solenoid to crank the engine.

 

And thanks for the Relay docs!

Edited September 21, 2022 by Handy Don

[gwest_ca-(File Mod) 11,046]

The START terminal on the ignition switch only powers the coil in the switching relay which closes the contacts.

Now the IGNITION terminal on the ignition switch powers the dark green #30 on the switching relay and since it is now closed passes power to the #85 dark blue on the start relay.

 

The START key position requires both the IGNITION and START terminals to be powered at the same time for the starter to work.