SMTA electrical issues revisited

Some of you may remember my post of a couple of months ago about the light switch starting my tractor whether the push/pull switch was in or out. I replaced the push/pull switch and all was well until it wasn't. Yesterday the tractor cranked but wouldn't start. It started really well with the light switch again. The question is did I spent $36.00 for a bad switch or do I have other issues? I am challenged when it comes to electrical work, but if anyone has a good idea for me I would really appreciate it. I checked very carefully for rubbed insulation and other grounding issues. I took the light switch box off and lined it with rubber inner tube and epoxy. Hoping for some insight. Thanks, Ellis
 
I just want to qualify exactly what is happening.

It cranks and turns the engine over, but will not start? Then when you pull the light switch out, you can crank again and it will start up?

If that is correct it sounds like the Light switch is completing the ignition circuit.

That sounds like a loose wire somewhere in the ignition circuit in the dash and the light switch is "back feeding" current to allow the tractor to run.

Is it wired as it was originally or has stuff been changed over the years?
 
So if I am reading this right you have an ignition switch that was working so you could start he tractor but now it is no working again but you can turn on the light switch and it starts?? Correct?? If that is the case it sounds like you have the wiring really mess up a lot. Ignition and lights should be circuits of there own and not have any thing to do with each other, other then being powdered by the battery. Ignition should be wired so the switch has one side with battery power an the other side going to the ignition coil not hook to the lights in any way. But from what your saying it sounds like you have it wired so the ignition switch is some how hook to the lights and so your burning out the ignition switch by pulling the amp draw of the lights threw the ignition switch so it has to high an map going threw the ignition switch
 
I'm sorry, I should have said 6 volt, positive ground, electronic ignition. It has a new wiring harness and huge battery cables and an Optima battery. I
acquired the tractor in 1992. My Uncle was the previous owner and he had it re wired. It charges well with the old generator. You pretty much got it
correct. Sometimes just turning the lights on starts the tractor. I know this is really simple but I can't figure it out. Ellis
 
Your answer to the other guy you say new wiring harness so is the new as in new you just installed it or new 26 years ago?? If 26 years old good chance something has burned or shorted in the wiring where you cannot see it so it is doing funny things now.
 
a wire should attach to the load side of the amp gauge, and attach to the ignition switch. From the other terminal on the switch, a wire goes to the ignition coil and electronic ignition. The lights also attach to the load sde, and are connected to a fuse, then to the light switch. If a wire is burn,t or corroded in the harness going out of the oval box, it could connect them at that point. Jim
 
26 years old is old enough for it to have internal cracks shorts and well lets just say could well be where the problem is. 26 years old is antique and no way of know how good or bad it is. You cannot look inside a wire and know it is good bad or has a high resistance or other such problem
 
I'm not in agreement with the immediate conclusion that the no-fire condition is caused by the ignition switch.

To arrive at that I would have to pull a plug wire or center wire and check for spark as the engine is cranked.

If that is No Good then I would have to check via voltmeter, that voltage is reaching the distributor body, coil, ign module, etc.

If that is found No Good [b:25bb1d4f32]then[/b:25bb1d4f32] I would be looking at the ignition switch. Check both sides for voltage in both switch states.

Other than wires and connectors, the above is the entire ignition system. In the 6v positive ground system, the battery negative terminal also is connected to one side of the ammeter.
 
Ignition switch receives power from wire from L terminal of regulator. Same side of ignition switch as L wire attaches the terminal has a wire to fuse then from fuse to light switch to power it. Other terminal on ignition switch has wire to power coil. Only way light switch should make a difference is if loosing power from L terminal and a hot wire is contacting the light switch terminals or wire to lights and back feeding power to switch when light switch turned on.
Everything is just a guess unless you at least use a test light to check power in or out of switch when problem appears.
 
Make sure you have a ground from cover to the box a then to the post. If you lose the ground it will crank but not start. The box is the switch panel and the mounting for it .
 
(quoted from post at 14:32:21 07/29/18) I'm sorry, I should have said 6 volt, positive ground, electronic ignition. It has a new wiring harness and huge battery cables and an Optima battery. I
acquired the tractor in 1992. My Uncle was the previous owner and he had it re wired. It charges well with the old generator. You pretty much got it
correct. Sometimes just turning the lights on starts the tractor. I know this is really simple but I can't figure it out. Ellis

I am not convinced the lights have anything to do with the problem. Yes, I know you believe it does and you may very well be correct. However, the questions below would help me understand this puzzle.


- If turning the lights on starts the tractor, that suggests the light switch is providing power to the ignition. What happens if the light switch is turned off immediately after starting - does the tractor shut off?

- When the tractor does not start and you turn the lights on - do you leave the ignition switch on or turn it off? If the light switch is powering the ignition it should start with lights on and ignition off.

- You state, "sometimes just turning the lights on starts the tractor". What do you do to start the tractor when turning the lights on, "sometimes" does not work?

- Finally, if the lights are powering the ignition, do you ever have to turn the lights off before the tractor will stop?
 
Though important for some functions, I think the ground of the box in this case is not important. The issue (opinion) is power in and power correctly out. Nothing in the light circuit, or ignition is grounded in the box. Jim
 
Well i will tell you this , i don't know whos fingers were in your wiring , BUT you have a messed up mess if you ing. switch is going thru the light switch . Yes you can piggy back the hot wire going to the ing switch off the the hot wire from the amp gauge . BUT since i don't know what a cluster you have i am not going to dig into this mess since the main harness only has few wire . Ya should have three wires going to the Gen/ Alt. IF done correctly one wire going to the Coil feed with two wires coming off the Reg. going to the dash with one wire going to the Amp gauge and one wire going to the light switch then one wire off the other side of the amp gauge going down to the hot post on the starter where the main battery wire is . Then off the light switch you should have Two wires one going to the head lights and one going to the rear light. This is NOT rocket science and not computer driven . BUT god only knows what someone did before you and how it is wired now. as in my years of working on tractors and dealing with Farmer repairs i have seen ROMEX , extension cords , wall plugs , wire nuts , masking tape hose clamps small nails bent around and smashed shut garden hose fuel line used for insulation bolts to replace fuses Switc h boxes house light switches and god only knowws what else . So when i run into someones mess i have a pair of side cutters and i am not afraid to use them and it ALL gets cut out and trash canned and i BUILD a correct harness made to the correct wire size and color .
 
Good Questions, Thanks If I start the tractor with the light switch, and turn the lights off it stops the tractor.
The lights start the tractor no matter the position of the on/off switch.
Sometimes the light switch will not start the tractor and it starts normally with the on/off switch
Sometimes the lights will stop the tractor and sometimes I have to use the on/off switch.
I can't begin to tell you how confused I am. Ellis
 
(quoted from post at 17:20:57 07/30/18) Good Questions, Thanks If I start the tractor with the light switch, and turn the lights off it stops the tractor.
The lights start the tractor no matter the position of the on/off switch.
Sometimes the light switch will not start the tractor and it starts normally with the on/off switch
Sometimes the lights will stop the tractor and sometimes I have to use the on/off switch.
I can't begin to tell you how confused I am. Ellis

Where do live? Maybe someone posting here lives "around the corner" and could help you in person.
 
(quoted from post at 12:20:57 07/30/18) Good Questions, Thanks If I start the tractor with the light switch, and turn the lights off it stops the tractor.
The lights start the tractor no matter the position of the on/off switch.
Sometimes the light switch will not start the tractor and it starts normally with the on/off switch
Sometimes the lights will stop the tractor and sometimes I have to use the on/off switch.
I can't begin to tell you how confused I am. Ellis

There is like 4 wires on this thing. You need a good volt meter and wiring diagram.

As I recall it is power to the meter(maybe regulator) and to the switch, then to the coil.

Lights have nothing to do with it running. Lights were an option back then.

Just take the panel apart and trace out the wires.
 
(quoted from post at 09:20:57 07/30/18) Good Questions, Thanks If I start the tractor with the light switch, and turn the lights off it stops the tractor.
The lights start the tractor no matter the position of the on/off switch.
Sometimes the light switch will not start the tractor and it starts normally with the on/off switch
Sometimes the lights will stop the tractor and sometimes I have to use the on/off switch.
I can't begin to tell you how confused I am. Ellis

Ellis,

I believe you have two problems. Yes, I believe you are correct the lighting circuit is one of them and adding to the confusion.

First, lets consider the ignition side, the push pull switch as you call it. If you have the original switch you replaced a few months back, check it and the replacement switch that is currently on the tractor. Both switches may be good, suggesting the problem is a loose connection in the wiring. Also, see the post from ih560. If both switches check bad, check the wiring for additional load (as others have posted) through the switch before replacing the switch with a new one. Once you get the ignition circuit working correctly it will not be so apparent the lights can also start the tractor. Could it be that the lights were sometimes powering the ignition for a long time and you did not notice it until the ignition circuit developed an intermittent condition...? This is why I say the lighting circuit adds the confusion.

Second, lets consider lighting circuit. Since the problem is intermittent (my understanding) it suggests a bare wire etc. is somehow coming in contact with the ignition circuit. This is not a big deal since it is simply supplying 6 volts to a circuit that is already is supplying 6 volts. However, in this case it is confusing. Since the light switch has to be on for the condition to occur, look for the problem after the light switch and before the lights.

You are getting a lot of support here from people more knowledgeable than this writer, so I will bow out. Hopefully this post was helpful to you.

Let us know what you find.
 

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