thermo-start issues

[thepumpguysc]

bad switch.?? not turning it correctly.??

 

[bazman82]

bad switch.?? not turning it correctly.??

There is only one way to turn the key for that light to come on. It could be a bad switch but wouldnt power not be supplies to the thermostart if that was the case? There is an electro valve that controls the fuel to the thermostart that has 1 wire hooked to it. I have a picture of it on page of this thread. Its number 62. It has power as well. Would this affect the thermostart heating up if it was bad?

 

[thepumpguysc]

If I remember correctly, u push IN on the key & turn it to the LEFT to energize the thermo-start..

 

[bazman82]

If I remember correctly, u push IN on the key & turn it to the LEFT to energize the thermo-start..

Is that for farmtracs? I believe the method to energize a thermostart varies between tractors. I'll give it a shot when I get home but I know I have tried turning it left but never pushed it in and tried it.

 

[Texasmark]

Seems you identified a wiring problem. My first guess would be to get a helper and a voltmeter. Have the helper energize the TS function and you check the voltage between the TS input spade lug (not the interconnecting wiring lug on the TS spade) and the case OF THE TS. You should have 10V or more.

IF not, check the same lug to battery -. 10v min. Ok move on, nada, clean up the threads of the intake manifold....not making a good ground.

Next is the wiring lug attached to the TS input spade. High temps encountered over the years could cause corrosion of that terminal and reduced continuity whereby the voltage is dropped across the wire to terminal crimp which will cause it to get hot....easy way to detect.....if oxidized or hot, clip the wire and crimp on a new terminal to nice and shiny wire.

Next would be the same terminal type problem at the ignition switch or a high current relay that the ignition switch operates...get a wiring diagram or trace the wiring.

Next would be the switch terminal interface and if not that, it's internal contacts.

 

[bazman82]

Seems you identified a wiring problem. My first guess would be to get a helper and a voltmeter. Have the helper energize the TS function and you check the voltage between the TS input spade lug (not the interconnecting wiring lug on the TS spade) and the case OF THE TS. You should have 10V or more.

IF not, check the same lug to battery -. 10v min. Ok move on, nada, clean up the threads of the intake manifold....not making a good ground.

Next is the wiring lug attached to the TS input spade. High temps encountered over the years could cause corrosion of that terminal and reduced continuity whereby the voltage is dropped across the wire to terminal crimp which will cause it to get hot....easy way to detect.....if oxidized or hot, clip the wire and crimp on a new terminal to nice and shiny wire.

Next would be the same terminal type problem at the ignition switch or a high current relay that the ignition switch operates...get a wiring diagram or trace the wiring.

Next would be the switch terminal interface and if not that, it's internal contacts.

This is where I lack in experience. I am assuming TS = trigger switch. Trouble shooting electronics is definitely not my strong suit and I mostly end up replacing things till it works...while this helps me gain the experience of working with that stuff, it becomes expensive after awhile.. I think at some point this week I'll fire up the tractor and park it in the shop to take the dash off and try testing the voltage. I do have a wire diagram as I do have the workshop manual but the wire diagram is all greek to me.

 

[Texasmark]

This is where I lack in experience. I am assuming TS = trigger switch. Trouble shooting electronics is definitely not my strong suit and I mostly end up replacing things till it works...while this helps me gain the experience of working with that stuff, it becomes expensive after awhile.. I think at some point this week I'll fire up the tractor and park it in the shop to take the dash off and try testing the voltage. I do have a wire diagram as I do have the workshop manual but the wire diagram is all greek to me.

TS...Thermo Start device.

Think about a water pipe. To get a given flow of water it takes so much head pressure and a certain sized pipe of a certain internal resistance. If you reduce the pressure or the size of the pipe, or the interior of the pipe becomes rough, or in comparing a rough interior to a smooth one, you will have reduced flow.

In electricity, the load (the Thermostart device) requires a certain flow of electrical current to heat to the required temperature to make it work. Bad connections, or corroded wire, or a low battery voltage will do the same thing as is the case with water.

A crude tester would be a 12v light bulb with a couple of wires attached. Put the bulb across the battery and check out the luminance. Take the bulb and with one wire on the battery - terminal, use the other terminal to explore your wiring back to and including the selector (ignition) switch. The light will not be as bright as when directly across the battery, but for a good connection, with the TS function energized, it will still be bright. If it dims down or goes out, you just found your smoking gun.

 

[bazman82]

TS...Thermo Start device.

Think about a water pipe. To get a given flow of water it takes so much head pressure and a certain sized pipe of a certain internal resistance. If you reduce the pressure or the size of the pipe, or the interior of the pipe becomes rough, or in comparing a rough interior to a smooth one, you will have reduced flow.

In electricity, the load (the Thermostart device) requires a certain flow of electrical current to heat to the required temperature to make it work. Bad connections, or corroded wire, or a low battery voltage will do the same thing as is the case with water.

A crude tester would be a 12v light bulb with a couple of wires attached. Put the bulb across the battery and check out the luminance. Take the bulb and with one wire on the battery - terminal, use the other terminal to explore your wiring back to and including the selector (ignition) switch. The light will not be as bright as when directly across the battery, but for a good connection, with the TS function energized, it will still be bright. If it dims down or goes out, you just found your smoking gun.

So I have done the 12v light test before I replaced the Thermo-start. I was getting a bright light from the TS but I didn't check it to the battery itself to see a comparison. I will check this out when I get home and see what happens. I can say it never dimmed down or went out from what I remember.

 

[Texasmark]

So I have done the 12v light test before I replaced the Thermo-start. I was getting a bright light from the TS but I didn't check it to the battery itself to see a comparison. I will check this out when I get home and see what happens. I can say it never dimmed down or went out from what I remember.

Remember, the TS has to be energized....gotta have current flowing.....course, something just hit me. If there is no current flowing, like you don't have continuity all the way from Battery + through the TS circuit wiring to Battery -, there is no voltage drop along the way. The light stays the same brightness all the way down the line, high resistance or not. That's where a multimeter comes in handy as you can go to the Ohms scale and check your resistance from source to load and find a high resistance connection if one exists. Multimeters are readily available and cheap...like I use HF meters and last one i bought was abour 5 bucks and it still works great and that was so long ago I forgot when I bought it. They come with instructions on how to test circuitry with them. Would be worth the investment.

 

[bazman82]

Remember, the TS has to be energized....gotta have current flowing.....course, something just hit me. If there is no current flowing, like you don't have continuity all the way from Battery + through the TS circuit wiring to Battery -, there is no voltage drop along the way. The light stays the same brightness all the way down the line, high resistance or not. That's where a multimeter comes in handy as you can go to the Ohms scale and check your resistance from source to load and find a high resistance connection if one exists. Multimeters are readily available and cheap...like I use HF meters and last one i bought was abour 5 bucks and it still works great and that was so long ago I forgot when I bought it. They come with instructions on how to test circuitry with them. Would be worth the investment.

I have the HF multimeter. Got it free with a coupon I tested the TS (new one) last night with the 12v tester. While energized I am getting a fairly bright light. Maybe only slightly less dim than when I tested the battery +. I know the TS works since I put jumpers on it and it heated up. Any more wiring testing will have to wait though because its been cold out and I would prefer to move my tractor into my little shop before jumping into that. Plus I have lights in there. Its a pain to work on it sitting outside using flashlights and lanterns.

Anyways, sounds like I should be using the multimeter now. I assume I place one point of the MM to the battery + or battery - and the other point on the piece I want to test? I'll have to look up how to tell when I have high resistance though since I don't have much experience with the MM other than if you get numbers then its good and if nothing then its bad...Sorry if it seems like I am asking too many questions, electronics isn't my strong suit and I am more of a hands on learner so I am trying to do my best with how your explaining it.