4250 John Deere electrical problems

[Tennessee JR]

I have a small ground wire under the hood that has voltage showing. I unhooked breakers until it stopped. It was the tach and monitor breaker. I unhooked fuel,water temp,oil pressure etc on the engine and transmission. Any suggestions before I go further. thanks for any help.

 

[Janicholson]

I have a small ground wire under the hood that has voltage showing. I unhooked breakers until it stopped. It was the tach and monitor breaker. I unhooked fuel,water temp,oil pressure etc on the engine and transmission. Any suggestions before I go further. thanks for any help.

There are two types of ground wires. One is used to assure ground from one chassis place to another. Frame to engine straps are like that. The other is to ground a device that needs a ground. Like an instrument cluster, or a headlight. Those grounds will have voltage on them if they are disconnected with the device turned on (key on if required) voltage there is normal and allows the device to actually have a complete circuit. Jim

 

[Tennessee JR]

Thank you for your response. Hopefully I do not have a problem.

 

[Jim.ME]

Info for the future. The 4250 uses a set of two Technical Manuals. TM1259 Operation and Test Manual has the diagrams, diagnostic parameters, and testing procedures for the various systems. TM1353 Repair Manual has the "wrenching" info. You can use those Publication numbers to confirm you are getting the correct manuals if you search for them used or reprints from various places. Here is a link to the JD Bookstore, if you want to check there. The pair will run you about $600 from JD.

JD Ag & Turf Bookstore

 

[wore out]

I have a small ground wire under the hood that has voltage showing. I unhooked breakers until it stopped. It was the tach and monitor breaker. I unhooked fuel,water temp,oil pressure etc on the engine and transmission. Any suggestions before I go further. thanks for any help.

It would be interesting if you could post a photo of the wire and the area where it is located.

What problem were you having that got you started checking the voltage of "grounds"?

Were you finding voltage with the wire connected or did you disconnect it for testing purposes?

 

[Tennessee JR]

Info for the future. The 4250 uses a set of two Technical Manuals. TM1259 Operation and Test Manual has the diagrams, diagnostic parameters, and testing procedures for the various systems. TM1353 Repair Manual has the "wrenching" info. You can use those Publication numbers to confirm you are getting the correct manuals if you search for them used or reprints from various places. Here is a link to the JD Bookstore, if you want to check there. The pair will run you about $600 from JD.

JD Ag & Turf Bookstore

Me and son talked about we need to get a set of manuals the other day. Would be money well spent. Thank you.

 

[used red MN]

Shot in the dark, but look around on the air filter housing and on the air tubes between it and engine, this may be a connection to the air filter restriction sensor. When you say “ground wire” I would guess it has an eyelet on it, this would contradict my theory because I would almost want to believe a 50 series would have a plug to connect to that sensor.

 

[Tennessee JR]

It would be interesting if you could post a photo of the wire and the area where it is located.

What problem were you having that got you started checking the voltage of "grounds"?

Were you finding voltage with the wire connected or did you disconnect it for testing purposes?

It was located close to the starter relay on the fire wall and ran into the instrument cluster. We put a reman motor in and had 2 wires I was not sure where they went. (Had pictures but lost phone) They had voltage while in hooked.

It would be interesting if you could post a photo of the wire and the area where it is located.

What problem were you having that got you started checking the voltage of "grounds"?

Were you finding voltage with the wire connected or did you disconnect it for

Shot in the dark, but look around on the air filter housing and on the air tubes between it and engine, this may be a connection to the air filter restriction sensor. When you say “ground wire” I would guess it has an eyelet on it, this would contradict my theory because I would almost want to believe a 50 series would have a plug to connect to that sensor.

I will look tomorrow. Thank you

 

[wore out]

Shot in the dark, but look around on the air filter housing and on the air tubes between it and engine, this may be a connection to the air filter restriction sensor. When you say “ground wire” I would guess it has an eyelet on it, this would contradict my theory because I would almost want to believe a 50 series would have a plug to connect to that sensor.

I think you may be on the right track, UR, the air cleaner restriction sensor would have a 2-wire plug with a wire with an eyelet dangling from it, I forget where that ground wire should be attached.