520 electrical gremlins

[Handy Don 12,237]

1 minute ago, gwest_ca said:

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.

Garry i think we might be looking at different model diagrams. I'm looking at '91-'97.

Here, the purple wire to pin #30 on start relay is ALWAYS hot with 12v and the blue wire to pin #35 goes hot with 12v when key moves to Start position and all safety interlocks are in appropriate states.

 

If you take the always hot purple wire and put it to pin #35, the relay will ALWAYS be energized. If you then move the blue wire to pin #30, it'll go hot as soon at the ignition goes to ON as long as all of the safety locks are in appropriate states AND since the Start relay is already energized, pin #85 will go hot with 12v and energize the Starter solenoid via the light blue wire.

[gwest_ca-(File Mod) 11,048]

By chance are you looking at a colored diagram? At some point in the color process I realized many of the switches and relays were not illustrated correctly. Some needed to be flipped top to bottom and/or side for side.

Revised a bit and moving closer to the conversation

 

 

Notice I flipped the Neutral Switch and Pto Switch in this one.

The original Neutral shows the Br being common but it is not. The Pu is common.

The original Pto shows Pu being common but it is not. The Dk Gn is common.

Looks like I also changed the Lt Bu to Dk Gn to the Switching relay but have forgotten why.

 

[huey 7]

17 hours ago, Handy Don said:

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!

 

Ok for reference I just purchased this tractor not running and has been sitting for awhile i have got it to run and the wiring looks in good condition and not messed with. Now for the ignition switch wires the ("S"TAN) ("I"ORANGE) ("A" PINK)  ("B" is RED) ("R" not used) When I was talking about testing relays i possibly could of had the numbers reversed i was going of memory thanks for all the help. Thinking i'm going to look for a ignition switch!

 

Edited September 21, 2022 by huey

[Handy Don 12,237]

2 hours ago, huey said:

Ok for reference I just purchased this tractor not running and has been sitting for awhile i have got it to run and the wiring looks in good condition and not messed with. Now for the ignition switch wires the ("S"TAN) ("I"ORANGE) ("A" PINK)  ("B" is RED) ("R" not used) When I was talking about testing relays i possibly could of had the numbers reversed i was going of memory thanks for all the help. Thinking i'm going to look for a ignition switch!

 

Well those are the correct colors at the ignition switch. So still no smoking gun.

Somewhere there is something amiss. Right now I think it is the switch itself. 

Can you get enough access and have you enough confidence to disconnect (and safely insulate) the orange and tan wires and then test the switch itself for continuity?

In OFF position, 12v at "B" only

In On position, 12v at B, A, I (I'm not sure about R) and zero at S

In Start position, 12v at B, S, I (not sure about R) and zero at A

 

From @gwest_ca's note, I'm now at sea on how to correlate what's there with what should be there.

As painful as it will be, @huey, I think you have no choice but to print out one of the colored 91-97 diagram (as big as you can) and then start making annotations of what you actually have and any variations--especially at the relays using the numbered pins in your notes.

 

[huey 7]

2 hours ago, Handy Don said:

Well those are the correct colors at the ignition switch. So still no smoking gun.

Somewhere there is something amiss. Right now I think it is the switch itself. 

Can you get enough access and have you enough confidence to disconnect (and safely insulate) the orange and tan wires and then test the switch itself for continuity?

In OFF position, 12v at "B" only

In On position, 12v at B, A, I (I'm not sure about R) and zero at S

In Start position, 12v at B, S, I (not sure about R) and zero at A

 

From @gwest_ca's note, I'm now at sea on how to correlate what's there with what should be there.

As painful as it will be, @huey, I think you have no choice but to print out one of the colored 91-97 diagram (as big as you can) and then start making annotations of what you actually have and any variations--especially at the relays using the numbered pins in your notes.

 

Ok I can for sure say it isn't the key switch as i also have a c-120 that works properly and thought i would check and same key switch so i switched the switches out and still no power at the solenoid. When i try to crank the 520h the seat dummy light comes on! Ok starting with the relays (KILL RELAY) #30 orange ,#86 black, #85brown, #87 yellow (SWITCH RELAY) #30green, #86black, #87purple, #85tan, #87a orange (START RELAY) #30light blue, #86black, #87white, #85purple. Before too long i'm going to remove all wiring and just wire up what it needs to run but i have too much time invested to give up...lol If the illustration above is correct i think in my start relay the #30light blue and #87white are reversed

Edited September 21, 2022 by huey

[gwest_ca-(File Mod) 11,048]

2 hours ago, huey said:

Ok I can for sure say it isn't the key switch as i also have a c-120 that works properly and thought i would check and same key switch so i switched the switches out and still no power at the solenoid. When i try to crank the 520h the seat dummy light comes on! Ok starting with the relays

(KILL RELAY) #30 orange ,#86 black, #85brown, #87 yellow

These are correct

Bold are not correct

 

(SWITCH RELAY) #30green, #86black, #87 purple, #85 tan, #87a orange

#87 should be dark blue and goes to #85 on the start relay below

 

(START RELAY) #30 light blue, #86 black, #87 white, #85 purple.

#30 should be purple and have battery voltage at all times - even with the key off. It may be on #85 below.

#87 should be light blue and is the wire that goes to the starter motor.

#85 should be dark blue and is the wire coming from #87 on the switching relay above

 

Quote

 

Have seen wire colors fade and change with UV light so possibly they are not clear any more. 

There should be only one purple going to start relay only.

 

Have an ohm meter? Disconnect the battery negative cable and use the ohm meter to confirm where the wires go.

With battery disconnected you can not damage your meter.

[953 nut 55,324]

2 hours ago, huey said:

Before too long i'm going to remove all wiring and just wire up what it needs to run

Please don't do that, we want you to whip this situation and celebrate your victory with you.

Here is the drawing and a table on your ignition switch that shows wha terminals are connected when in OFF, START and RUN positions.

[huey 7]

Ok i'm not sure on the year but definitely between the 91-97 years. the purple wire you are talking about in the diagram (mine is white) with 12v power all the time and is sitting on #87. My light blue wire that goes to the solenoid is sitting on #30 (i'm pretty sure i need to switch these two around) Also the dark blue wire you are referring to from the switch relay #87 to #85 on the start relay is definitely purple on my tractor and none of the wires are faded at all that i can tell doesn't matter anyway as long as they are in the right location. Maybe my colours are a certain year only or they maybe ran short on some of the wire colours that day of the build. I will attempt to switch my white and light blue wires around tomorrow and let you know what happens thanks for all the help i might even have a few hairs left on my head when its all over...lol 

[953 nut 55,324]

 

38 minutes ago, gwest_ca said:

(SWITCH RELAY) #30green, #86black, #87 purple, #85 tan, #87a orange 

#87 should be dark blue and goes to #85 on the start relay below

 

(START RELAY) #30 light blue, #86 black, #87 white, #85 purple.

#30 should be purple and have battery voltage at all times - even with the key off. It may be on #85 below.

#87 should be light blue and is the wire that goes to the starter motor.

#85 should be dark blue and is the wire coming from #87 on the switching relay above

Good explanation Garry, thanks for all you do. I looked at the wiring diagram for 1994 520-H and confirmed that it is the same.

 

[953 nut 55,324]

@huey, just for grins before you change any wires around lets do a little experiment.

Presuming you have 12 volts on # 30 of the start relay socket with the relay removed run a small jumper wire to # 87 of the socket and see if the solenoid closes. Same thing as the relay switch closing.

Now remove the switching relay and insert the start relay into it's socket. With all safety switches in the proper position and the ignition switch in the on position see if you have 12 volts at # 30 in the socket, if you do then use the small jumper to the # 87 of the socket and see if the start relay closes and the solenoid closes.

[Handy Don 12,237]

I'm gonna stand back and sip my lemonade while @953 nut and @gwest_ca lead on so we don't get any "wires crossed". You guys are on this.

Nice work swapping the switches, @huey! 

 

[gwest_ca-(File Mod) 11,048]

3 hours ago, huey said:

Ok i'm not sure on the year but definitely between the 91-97 years. the purple wire you are talking about in the diagram (mine is white) with 12v power all the time and is sitting on #87. My light blue wire that goes to the solenoid is sitting on #30 (i'm pretty sure i need to switch these two around)

You do not need to switch them because terminal 87A is not used. This relay does not have a 2nd function. As long as the power can get from 87 to 30 or 30 to 87 does not matter.

Made the change for you below

 

Also the dark blue wire you are referring to from the switch relay #87 to #85 on the start relay is definitely purple on my tractor and none of the wires are faded at all that i can tell doesn't matter anyway as long as they are in the right location. Maybe my colours are a certain year only or they maybe ran short on some of the wire colours that day of the build. I will attempt to switch my white and light blue wires around tomorrow and let you know what happens thanks for all the help i might even have a few hairs left on my head when its all over...lol 

 

I do not see what is wrong. Only other possibility is the black relay grounds are not good.

[huey 7]

Do these relays ground between the battery and pto micro switch? If so I have  cleaned them up.

[gwest_ca-(File Mod) 11,048]

1 hour ago, huey said:

Do these relays ground between the battery and pto micro switch? If so I have  cleaned them up.

I think they do.

Have a test light?

Ground the clip and check the ground wire at the relay. If the ground is bad it should light the tester when the relay is activated. A volt meter works also. You will see 12 volts if the ground is bad.

[953 nut 55,324]

I am reasonably sure you are accurately diagnosing the relay wiring but just to be sure I labeled a picture of the socket. Also I wanted to show the type of terminals and mention that the terminals can be released by using a small flat screw driver to depress the tab on the back of the terminal if needed.

 

[huey 7]

17 hours ago, gwest_ca said:

 

I do not see what is wrong. Only other possibility is the black relay grounds are not good.

Ok without switching any wires yet, here i go i jumped my #87(white) 12volt all the time to #30 light blue  on the start relay and solenoid engaged. Now i removed the switching relay and tried to jump #30 (dark green) to  #87 purple on mine and nothing happens i feel the start relay click but solenoid doesn't engage. When i test my #30 (dark green) on the switching relay there is no 12 volt power with key off but have 12 volt power with key on then when i turn to start i loose power again! Anymore suggestions i can start the tractor running a wire directly to the solenoid and pretty sure micro switches are working because if i move either one while running it stalls the tractor. Ok something else i tried is i ran a jumper wire from #87a(orange) and joined to #30 (green) on the switching relay base with all relays plugged in and tractor starts with the key but i know its not right way and bypassing the safety switches.

Edited September 22, 2022 by huey

[953 nut 55,324]

5 hours ago, huey said:

When i test my #30 (dark green) on the switching relay there is no 12 volt power with key off but have 12 volt power with key on then when i turn to start i loose power again! Anymore suggestions

Your ignition switch should have power to the Battery, Ignition, Start and R (which is not used) in the start position. Take a look at post # 32. Sounds like the ignition switch is not performing properly. Time for a new 103990.

5 hours ago, huey said:

Ok something else i tried is i ran a jumper wire from #87a(orange) and joined to #30 (green) on the switching relay base with all relays plugged in and tractor starts with the key but i know its not right way and bypassing the safety switches

Interesting! The 87a wire of the switching relay is connected to the ignition switch "I"  terminal and looking at the wiring for the Kill relay I think all of the safety switches would be able to drop out the kill relay if opened once you have restored the seat switch function.

[gwest_ca-(File Mod) 11,048]

Try a jumper between the orange and brown at the seat switch and see what happens.

[huey 7]

6 minutes ago, gwest_ca said:

Try a jumper between the orange and brown at the seat switch and see what happens.

I do have it jumped  between  orange and brown  under the seat still loose power on green at switching relay when trying to crank it and have also changed the switch  from a c120 which is the same thing  still not working 

[gwest_ca-(File Mod) 11,048]

Try jumper from brown wire at seat to purple wire at pto switch. Pto must be off.

 

Next

 

Try jumper from purple to green at the pto switch.

[gwest_ca-(File Mod) 11,048]

19 minutes ago, huey said:

I do have it jumped  between  orange and brown  under the seat still loose power on green at switching relay when trying to crank it and have also changed the switch  from a c120 which is the same thing  still not working 

Make sure you are getting 12 volts at the seat switch brown wire with the key in START.

If not the jumper between the orange and brown is not working = poor connection

 

Next

 

Make sure you are getting 12 volts at the pto switch purple wire with the key in START.

[huey 7]

8 hours ago, gwest_ca said:

Make sure you are getting 12 volts at the seat switch brown wire with the key in START.

If not the jumper between the orange and brown is not working = poor connection

 

Next

 

Make sure you are getting 12 volts at the pto switch purple wire with the key in START.

Ok checked seat wires orange has power key on and start, brown wire  has power key on but no power  at start position  have power at motion and pto with key on but loose power in start position? What do I need to look at to get power at brown wire I  start position?

[gwest_ca-(File Mod) 11,048]

56 minutes ago, huey said:

Ok checked seat wires orange has power key on and start,

brown wire  has power key on but no power  at start position - This indicates the ignition switch has failed - ignition terminal power lost when key turned to start position.

 

With failed ignition switch above the results below are the expected result.

have power at motion and pto with key on but loose power in start position?

What do I need to look at to get power at brown wire I  start position?

Does not make sense that the orange is fine in ON and START key positions but the brown is not. Same wire and key positions with a jumper in the seat switch brown wire should perform same as orange wire.

[huey 7]

2 hours ago, gwest_ca said:

Does not make sense that the orange is fine in ON and START key positions but the brown is not. Same wire and key positions with a jumper in the seat switch brown wire should perform same as orange wire.

Ok with seat jumper not installed orange has power at the seat connection key on and start, brown has power key on but no power at start position. now with seat jumper installed i check the orange at the switch and kill relay and power there with key on and start. I check the brown at the kill relay and has power key on but no power at start position? I don't understand it at all i did remove my key switch from my c120 and tried it but still same result!

[gwest_ca-(File Mod) 11,048]

Have you checked the ignition switch function with a test light or voltmeter? Click on the pictures to see the description.