Replaced solenoid, tractors "hot" all the time

marmon77

Member
Replaced solenoid on Ford 800 with like solenoid put wires in exact same place but when I went to put the Neg. on the battery it would spark and started would start spinning? It has the original push button on tranny cover, can they go bad? Have 3 wires on Lg. bolt from batt. alt. and key switch. Wire runs from {S} to terminal block. One wire from bottom Lg. terminal to starter. Worked on it for hours, used [2] different solenoids but every time I touched a test light to any part of the tractor it would light up. Any ideas? Thanks
 
Are you getting a solenoid made for a tractor or one made for a car or truck they are in fact different. Ones for a car or truck use a power line to work the solenoid and one for a Ford tractor use a ground to work the solenoid
 
make sure you have the correct solenoid FIRST.

Next, make sure the line to the thumb switch is not permanently grounded. IE.. shorted switch, or chaffed wire.

post back
 
Replaced solenoid on Ford 800 with like solenoid

Did it just look like the old one or was it identical electrically on the inside? There are solenoids that look the same on the outside but that are different electrically inside.
 
Funny, I am having exact same problem on my 850 right now. I am going to switch out the push button with a new one and see if that corrects the problem. But I think it is these CHEAP import starter solenoids. Cracked one open to see exactly how they work. We might accidently be twisting the connecting poles when tightening the cables. When I look inside the twisting might cause the contact block on the pole to get out of position and touch the solenoid plate. Not sure, but a starter solenoid is not complex. My problem started with an existing solenoid that went crazy. I had to disconnect my battery to stop the starter motor from spinning after the engine quit running.
 
No reason to play with the starter button just pull the wire off the solenoid that goes to the starter button. Then use a VOM and make sure the wire/switch is not shorted to ground. If it is then the wire or switch is bad if it is not shorted to ground and you hook up the battery and it does the same thing the solenoid is the wrong one or a new bad one
 
the thumb button just grounds... don't replace it to check it.. just ground the little terminal / wire to test the solenoid.
 
"Wire runs from {S} to terminal block"

Do you have 1 or 2 small terminals on solenoid?

According to diagrams I have, if it has 2 small terminals one should receive power from the switch (one post on terminal block) and other terminal to start button by gear shift. Start button supplies ground to activate the starter

If one small terminal then one of the large terminals should be marked BAT beside it. Activating coil is internally connected to this post for power and is activated by grounding the small post.

One terminal solenoid should not have a wire from terminal block.
 
The first one I put on was new from Tractor Supply with only (1) small terminal, the second was for a Ford truck with (2) small terminals. Both seemed to do the same thing unless I wired it wrong or crossed. I will recheck.
So the wire from push start goes to (S) terminal or goes to terminal block?
Also you may be right about them touching internally I noticed that it wouldn't "run on" until I snugged the nuts down, then couldn't get it to stop unless I pulled off Neg. batt. wire.
I will try your responses as I will be where the tractor is located this weekend and post back on Monday. Thank you all
 

The wire from the starter button always goes to the S terminal on the solenoid, never to the terminal block. If it's a 4 terminal solenoid, a wire from the switched side of the terminal block goes to the I terminal (the 2nd small terminal) on the solenoid.

Might I ask what the tractor had on it before you replaced the solenoid? If it was a 3 terminal, it should be replaced with a 3 terminal. If a 4 it should be replaced with a 4.

However, as has been said, you need the correct 4. You need one that applies a ground to close its contacts. 4 terminal solenoids that apply power to close the contacts are much more common. That's likely what your truck solenoid is. Unless you want to reconfigure wiring this latter type will not work.
 
i had that same problem too on my naa 12 volt the four post solenoid would not work ti has a s and a i on it go to napa and gut one that is pos and ground go from battery side of solenoid with a jumper wire to the pos side front and hook starter button to the back see if this works
 
It had a 3 post solenoid , I replaced it with a new 3 post and had same problem unless I bought a bad "new" one from Tractor Supply.
 
(quoted from post at 07:54:13 07/18/17) It had a 3 post solenoid , I replaced it with a new 3 post and had same problem unless I bought a bad "new" one from Tractor Supply.
et's establish a baseline starting point for your 3 terminal solenoid & then proceed from there. OK. Take the solenoid off, connect one large post to battery (no matter + or -, then small terminal to other battery post. Does it click? Repeat with other large post. Does it click?
Now, forget the two large posts and connect solenoid mounting base to battery and other battery terminal to small terminal. Does it click?
 

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