312-8 - Kill switch issues

[TC10284 111]

Just fixed up a 1987 312-8 with model number 21-12K804

 

Runs great. 

Issue I have now Is that the original key switch will allow the voltmeter to work, but the seat switch and the parking brake lights stay on constantly and as soon as I turn the key to Run. The other issue with this key switch is that it does not kill the engine when I switch to off. 

 

OK, so I swapped the key switch with another NEW, 5 pin key switch. That fixes the seat switch and the parking brake light issue, and the test switch lights up all lights correctly. 

However, with the new key switch, the voltmeter refuses to work, and turning the switch to Off still does not kill the engine. 

 

I have checked and cleaned the negative battery ground to the chassis. The two fuses are new, not blown. 

 

I'm not sure what else the issue could be at this point. 

[gwest_ca-(File Mod) 11,169]

The parking brake light and the voltmeter are powered by the same circuit.

 

The common between the voltmeter and the ignition switch is the ground.

 

What part number ignition switch did you use?

 

Garry

[TC10284 111]

I have been using one of these on this specific one, but similar have worked OK in my others WH that require 6 terminals on the key switch. 

https://www.amazon.com/dp/B073GCH7LV/ref=cm_sw_r_cp_apa_glt_fabc_YT7VQTVK33ZG3TVD76WJ?_encoding=UTF8&psc=1

[953 nut 56,612]

Check out this thread;

 

[gwest_ca-(File Mod) 11,169]

You have the wrong switch. I am surprised you have not smoked the ignition coil.

Should be using the 103991 switch. Added the unique 5-wire connector in red.

 

 

 

[TC10284 111]

Thanks guys. I appreciate that. 

 

My next issue is that I swapped it with an original key switch from what I believe is from a 211-X series. Definitely a WH though. It was still mounted to the plate and only has the key switch and the light switch and is bigger than a 300 series plate. 

 

Anyway, it exhibited the same behavior as the original key switch that came with the tractor - i.e. - seat switch light and parking brake lights come on and stay on. Neither switch kills the engine when switched to off. 

So I will order the correct model key switch for my tractor, but I believe I have some other wiring issue going on. 

Edited August 2, 2021 by TC10284

[953 nut 56,612]

8 hours ago, TC10284 said:

I will order the correct model key switch for my tractor, but I believe I have some other wiring issue going on.

Once the correct switch is installed let us know what (if any) problems are found and we will help you.

[TC10284 111]

This is what was ordered and should be here today. Part number matches. Will test and let you know. 

Ignition Switch for Toro/Wheel Horse https://www.amazon.com/dp/B00CNUIO4O/ref=cm_sw_r_apan_glt_fabc_SHXRBCR6TVDHXKBNHYNZ

[TC10284 111]

New key switch (mentioned above) is installed. Does better, but not quite there yet. Seat switch light is now off. Voltmeter works. However, parking brake light is still on, and engine still does not shut off when turning the key to Off position. 

Pics/video:

https://photos.app.goo.gl/vNoBMLxHXprNrDRE9

 

[gwest_ca-(File Mod) 11,169]

Brake light problem is most likely right at the switch for the parking brake.

With the engine running and switch OFF try adding a jumper ground wire to the black ground wire at the side of the ignition switch. Suspect that ground wire is broken somewhere. Make 100% sure the jumper is a ground. If it has battery power in it it will burn up the ignition coil.

Garry

[TC10284 111]

35 minutes ago, gwest_ca said:

Brake light problem is most likely right at the switch for the parking brake.

With the engine running and switch OFF try adding a jumper ground wire to the black ground wire at the side of the ignition switch. Suspect that ground wire is broken somewhere. Make 100% sure the jumper is a ground. If it has battery power in it it will burn up the ignition coil.

Garry

 

Do you know where that black ground wire on the switch goes to? 

 

My plan would be to jump it to the chassis, possibly where the battery negative terminal connects to. 

[953 nut 56,612]

3 minutes ago, TC10284 said:

My plan would be to jump it to the chassis,

[TC10284 111]

On 8/2/2021 at 7:14 PM, gwest_ca said:

Brake light problem is most likely right at the switch for the parking brake.

With the engine running and switch OFF try adding a jumper ground wire to the black ground wire at the side of the ignition switch. Suspect that ground wire is broken somewhere. Make 100% sure the jumper is a ground. If it has battery power in it it will burn up the ignition coil.

 

 

Connected a jumper wire that I know works (continuity test passed) to "G"  ground connector on key switch. Started engine. Connected other end of jumper to various ground points on chassis. Engine stayed running. 

 

Perhaps the ground wire to the ignition coil is not making contact in the wiring harness that goes to the engine? 

[TC10284 111]

Hmmm, I'm also wondering if there's something wrong with the wire that connects to the top of the ignition coil, which I believe, then runs to the main connector. 

 

This is in the one I posted about where the previous owner installed an ignition coil improperly, turned it over or ran it, and broke a coil mount. So I had to replace the bearing plate.

I suppose I should test that wire also. Maybe it got ripped and broke somewhere. 

 

I might be completely off base though. 

Edited August 6, 2021 by TC10284

[gwest_ca-(File Mod) 11,169]

That sure is possible.

[TC10284 111]

So I tested the cable that connects to the top of the coil, that runs down to the main connector, that then goes to the black/blue wire in the other end of the connector. 

I have continuity just behind the diode on the coil side of the wire to the other end. Past the diode, I have nothing. Is that by design or do I have a bad diode? I'm Assuming the diode is to disallow voltage from anything else going through the coil. And if it does, it blows. 

 

In your diagram it shows the diode is optional. Is it OK to cut the diode off (if it's bad) and just connect a straight wire? 

Edited August 6, 2021 by TC10284

[TC10284 111]

And BTW, your graphics and manuals are always so helpful. I appreciate you and everyone else that assists here! 

[TC10284 111]

That diode must be bad. I've tried continuity test with both polarity of the tests leads and then reversing and I get nothing when it has to go through the diode either way I do it. 

[gwest_ca-(File Mod) 11,169]

If there is a diode there that is what saved your ignition coil when the wrong switch was used.

Do you still have active Radio Shacks's?

Much safer having a diode in place since you have electrical problems.

Garry

[TC10284 111]

18 minutes ago, gwest_ca said:

If there is a diode there that is what saved your ignition coil when the wrong switch was used.

Do you still have active Radio Shacks's?

Much safer having a diode in place since you have electrical problems.

 

 

We don't have an active Radio Shack, but I'm OK with ordering it online. I found the diode model from your link and I'll see if I can get one.

I'd feel better about having it on there too. 

 

I did test it by cutting off the bad diode, and just crimping on one of the crimp-type of connectors and it resolved the engine kill issue. I'm still having the parking brake light come on, but I'm OK with that and will try to trace it down later. 

 

Thanks!

[TC10284 111]

The parking brake light was a simple issue with the switch. The metal arm had to be bent out and after that, it went off. 

 

I tried replacing the diode with a 1N4002 and after I put the diode in place, the switch would still not kill the engine. I made CERTAIN the diode was the proper orientation, according to the original diode. And I even tested with an ohm meter. From the end of the connector at the ignition coil, to the pin on the connection that runs to the key switch. I got around I think 3 ohms. I made sure it had continuity.

I had to remove the diode before the key switch would kill the engine. So I suppose I will just leave the diode out of the mix. 

[Handy Don 12,980]

Just one thought...

Measuring continuity of a diode with a VOM that puts only a small voltage and very small current through the diode may not suffice in this situation.

If you can, check the diode in series with something using the full 12 volts and drawing a decent current, like non-LED headlights, and see if it works as expected.

Edited August 15, 2021 by Handy Don

[TC10284 111]

15 minutes ago, Handy Don said:

Just one thought...

Measuring continuity of a diode with a VOM that puts only a small voltage and very small current through the diode may not suffice in this situation.

If you can, check the diode in series with something using the full 12 volts and drawing a decent current, like non-LED headlights, and see if it works as expected.

 

So, 12v battery on one side, and something like an old par36 bulb on the other end. 

 

What am I looking for? It working with positive on one side and not working when reversed? 

[Handy Don 12,980]

2 hours ago, TC10284 said:

 

So, 12v battery on one side, and something like an old par36 bulb on the other end. 

 

What am I looking for? It working with positive on one side and not working when reversed? 

Yep, that'll work. Looking for light one way and darkness the other way (how downright philosophical)!