starter solenoid

[boarnold]

First of all, I'm an idiot. I'm trying to wire in a solenoid to my farmall. It is a ford style solenoid with four posts. I have battery wire and alt going to one large post. The wire from the starter is going to another large post. A wire is coming from a push button starter and going to the smaller post labeled S. I have an ignition switch which sends 12v to coil and start button switch. I have 12v at the small post labeled s when I push the starter switch, but I don't have power to the large post that the starter wire is hooked to. Engine doesn't turn over. I've double checked all connections. I tried using another solenoid still with the same problem.

 

[used red MN]

Is the solenoid mounted to a ground? If not that could be your problem. But, when you say ..Ford style.. do you mean tractor or automotive? The tractor style solenoid likely requires a ground to the second small terminal, that is how a neutral safety works on many Ford tractors the switch on the gearshift or wherever provides a ground to the solenoids electromagnet coil. When you push the start button if that other small terminal becomes energized you need to make a ground wire for it.

 

[wore out]

As the other poster said, is the mounting base of the solenoid grounded?

LOTS of solenoid look the same but are connected differently internally.

What is the make and model number of the solenoids you have tried?

 

[boarnold]

https://www.napaonline.com/en/p/ECHSTH404?cid=paidsearch_shopping_dcoe_google

This is the solenoid that I have. I did do some research, and I saw that the solenoid might need to be grounded. I took a jump wire from the negative battery terminal and connected it to the metal frame of the solenoid. That didn't do anything. I don't know if that is even a proper test or not. I did check to see if the other small post energizes when I push the start button, and it does not. I don't believe that I tried putting a jump wire from the negative battery terminal to the other small post on the solenoid. Maybe that is what I need to try. ??

 

[Janicholson]

If the body of the Ford style solenoid is grounded, and the S terminal is given power, it will click loudly. If it is not clicking, the solenoid is bad. THe I terminal is not to be grounded, it will make contacts (or the wire you use hot. THe I terminal is used as a independent voltage source to bypass an ignition coil for starting. Jim

 

[used red MN]

Jim, I agree with your recommended test it should click. By him not getting the click he indicates he has had two bad solenoids. ?? Do you know if that type of solenoid relies on a ground for a pull in coil? I think it should still activate the magnetic coil when the S terminal is energized. Only other thing that I would suggest is to swap the connections on the large terminals and try that. Beyond that if this is a NEW 6 to 12 volt conversion who knows what might be going on. You say ..alternator wire.. so you have it set up negative ground, it needs to be. Where do you have the battery cable grounded? Where does your ignition and lights pick up power? Jim in correct, that solenoid is set up for an ignition bypass circuit, the ..I.. terminal, if that is the designation Ford uses should not be grounded in that case.

 

[Jim.ME]

I don't think swapping the cables on the big terminals will do much. The base needs a good ground. The I terminal does not need to be used unless a resistor bypass is needed and it should not be grounded.

Use a jumper wire to apply power to the S terminal once the base is well grounded. Eliminate the chance that the wire from the push button, or the push button are bad. A voltmeter can show voltage even if a wire won't pass current enough to operate something.

 

[boarnold]

I tried checking to see if the solenoid is grounded. I put the red probe of the multimeter to the positive battery terminal and the black probe to the body of the solenoid and I didn't see 12v. Could I run a wire from the battery negative terminal to the solenoid body? Could that work to ground the solenoid?

 

[Janicholson]

One other option to try. The ground might be through the starter (it appears to the solenoid as about .02 ohms or less). So the starter may be open. A way to test that is to test it off the tractor in your hand. With the big input terminal closest to the S terminal disconnected, put a ground to the big terminal closest to the I terminal and 12 v to the S terminal. this should make it click. Jim

 

[Jim.ME]

(quoted from post at 18:22:11 11/06/23) I tried checking to see if the solenoid is grounded. I put the red probe of the multimeter to the positive battery terminal and the black probe to the body of the solenoid and I didn't see 12v. Could I run a wire from the battery negative terminal to the solenoid body? Could that work to ground the solenoid?

To see if the solenoid has a grounded base use your multimeter set to ohms. Remove any power source from the solenoid and use the ohmmeter function to check between the ''S'' terminal and the metal base where the screw holes are, not the big terminals and base. It should have a very low reading, even 0.

A wire from the battery negative to the base metal where the screw holes are would be a ground. Then use another wire from the battery positive to touch the S terminal of the solenoid and it should click.

 

[teddy52food]

Are there any marks by the small terminals? If you have 12 volts comming from the switch to one terminal try grounding the other & see if it works. Maybe it is not a solonoid with a grounding base.

 

[used red MN]

Wonder if he solved his conundrum? My take is he had the solenoid unmounted when he found voltage at the S terminal when pushing his start button. When he grounded the solenoid due to a poor connection in his circuit the solenoid would not energize when the now grounded circuit was completed. Convinced he had voltage there from the button he never rechecked the circuit.

 

[boarnold]

I'm not able to get out the the Farmall until this weekend to try things out. I have a list of things to try though. I'm going to try to set the multimeter to horse shoe mode and put one probe (I don't think it matters which one) onto the frame of the solenoid and the other one to the S post. If it has a 0 reading or close to it I will try putting a wire from the negative battery terminal to the frame of the solenoid. If the multimeter reads something else, then I have no idea.

 

[boarnold]

The other small post has an I. I will try grounding that post. Although I've heard it is for something involving a resister to the coil. Whatever that means.

 

[Jim.ME]

I posted the schematic of the STH404 solenoid, which is what you posted you purchased, from the Echlin buyers guide. It is a grounded base solenoid. Properly grounding the solenoid base metal, where the mounting screws go, then providing power from the start push button will make that solenoid work, unless it is defective.

The ''I'' post [u:7e2cb18aa2]does not[/u:7e2cb18aa2] get grounded on that solenoid. When the solenoid is energized and the contacts for the starter motor circuit close that ''I'' terminal contact is closes as well and is used to send full voltage to the coil, bypassing a resistor, to improve spark only during cranking of the engine. Resistor is referring to a ballast resistor mounted and wired in ahead of the coil. They are commonly used to reduce the voltage/amperage passing through a coil, designed for use with 6 volt system, when said coil is used in a 12 volt system.

 

[teddy52food]

That is for the ign by pass so grounding it won't work either.

 

[boarnold]

One of the solenoids were no good. Also, I said that I was an idiot, I just had to clean up some grounds. Thanks for the help. Learning opportunity.

 

[Jim.ME]

Good to hear, Thanks for letting us know you got it.

 

[used red MN]

Yep, good to know you got it worked out. Sometimes on these conversions you never know what you may come up against, some folks that only know enough about electrical systems to be dangerous, can come up with some pretty..ingenious.. wiring and I am not talking about you. You are not an ..idiot.. you installed what was needed and with a little help got it to work. An example of an idiot is someone who removes the oil cap and fills it full! ; > )