# Ford/New Holland 2120 HSS Shuttle Shift Wiring



## Trey Fisher (Nov 11, 2020)

Does anyone have pictures of how their Control Module behind the center sheet metal, under the steering wheel and how both shift solenoids are wired in? No one close to me has a used harness and i can't afford a new one, so i was able to get my hands on a uncut harness that didn't have the shuttle shift pig tails from the factory. I know they can be wired in because for some reason the previous owner had them all splice in, including the three spade connectors going to the FNR selector at the steering wheel.

long story short, the harness was so cut up and ruined that i was fired to get a used one and now i can't figure out how he had them wired in, and it never dawned on me to take pictures before removing


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## BigT (Sep 15, 2014)

Howdy Trey,
I would go to your local New Holland dealer (if you have one?) and see if they would make a copy of the wiring diagram you need. 
Failing that, Tractorhouse.com has 25 each 2120's listed in salvage in their "dismantled machine" section. You may be able to prevail upon one of them to take a picture of the wiring you need. These guys are usually very helpful (it's good for their business).


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## Keith Davis (Dec 1, 2020)

I have my 2120 torn apart right now, so I grabbed the harness and snapped a picture for you. This morning I realized that I needed to also grab this "black box" that goes between the control module and the shift position switch. Here is also the wiring diagram for the HSS system. Let me know if you need more info or pictures.


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## Trey Fisher (Nov 11, 2020)

Keith Davis said:


> I have my 2120 torn apart right now, so I grabbed the harness and snapped a picture for you. This morning I realized that I needed to also grab this "black box" that goes between the control module and the shift position switch. Here is also the wiring diagram for the HSS system. Let me know if you need more info or pictures.





Keith Davis said:


> I have my 2120 torn apart right now, so I grabbed the harness and snapped a picture for you. This morning I realized that I needed to also grab this "black box" that goes between the control module and the shift position switch. Here is also the wiring diagram for the HSS system. Let me know if you need more info or pictures.


The picture you posted sadly didn’t help... the diagram you shared however was extremely helpful! My problems persists, though. Because this guy butchered my harness, I only have a few factory pigtails. I have managed to get 12V coming out of all but one wire (which I assumed is ground) coming from the Control Module. Shuttle Switch is BARELY pieced together, but seems to be working. 

My current problem is getting the tractor to engage in any gear. I’m having to use female spades on the FNR selector and no matter how I wire it, it refuses to go into any gear. I can’t see where these wires connect because if your wire loom and I wouldn’t ask you to separate yours just for this. The diagram was little to no help here because I’m missing so much. 

PS!! Come to find out the harness is from a similar New Holland that was a slightly smaller tractor so he had pieced this harness in. ALSO, I never had a Mode Switch (Turtle and Rabbit Selector) and everything worked normally beforehand. I’m not sure how this guy managed this but I don’t have the money to buy a new harness and there aren’t any used harnesses even remotely close. Just wish the damn thing would work like it should.


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## Trey Fisher (Nov 11, 2020)

Keith Davis said:


> I have my 2120 torn apart right now, so I grabbed the harness and snapped a picture for you. This morning I realized that I needed to also grab this "black box" that goes between the control module and the shift position switch. Here is also the wiring diagram for the HSS system. Let me know if you need more info or pictures.



I’ll post pictures of what I’m currently looking at tonight as I brought what I have inside to sit down and try to double check everything once again.


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## Keith Davis (Dec 1, 2020)

I can take closer pictures of each of the connectors so that you can see the wire colors going into each one. Likewise, point out some specific areas and I can give more detail as well. I'm still waiting on parts to show up to start the reassembly of mine anyway.


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## Trey Fisher (Nov 11, 2020)

Dude that would be a life saver. I’ll post pictures of what I’m looking at currently. This is how it was left mind you.


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## Trey Fisher (Nov 11, 2020)

Keith Davis said:


> I can take closer pictures of each of the connectors so that you can see the wire colors going into each one. Likewise, point out some specific areas and I can give more detail as well. I'm still waiting on parts to show up to start the reassembly of mine anyway.




Were you ever free to take anymore pictures by chance?..


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## Keith Davis (Dec 1, 2020)

Sorry Trey, I've been stuck on the honey-do list all week-end and the past 2 evenings are commitments with the kids. I'll try and remember to take pictures sometime over the next 3 evenings - Friday at the latest, for I am going to pick my parts up from the dealer on Friday to start putting my machine back together.

Oh yeah, your pictures show you are missing a lot! Do you have the connectors for the solenoids? Those are a pretty specialize connector. Reminds me of a electronic fuel injector connector.


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## Keith Davis (Dec 1, 2020)

OK I had the time tonight to take some pictures:








Here is the entire harness connected except for the mode switch (connector is the one at the very top of the picture). Shift solenoid valve is laying on the white plastic, HSS control module is flopped-over the right of the solenoid and the "black-box" is attached to the column base bracket. There is a single ground wire that comes out of the "black-box" and goes under one of the steering column base bracket bolts.








Here are the wires at the F-N-R switch at the end of the shifter.








This is the connector end of the F-N-R switch pig-tail.








This is the mating connector to the F-N-R switch pig-tail.








This is where 2 wires from the F-N-R connector go to the "black-box" which is not shown on the electrical diagram from the manual- it is only 2 terminals on the diagram.


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## Keith Davis (Dec 1, 2020)

This is the next connector the puts the F-N-R wires and the "black-box" into the rest of the HSS wiring.








Here is the mating connector to the "rest" of the harness.








This is a shot of the harness and the 2 pictures above this one - that connector is in the middle of the black taped wire "loop". The connector with the "A" wrote on it connects to the engine/front dash harness.








Here is the shift solenoid valve assembly with the harness attached. The single wire with eyelet on it is a ground wire that attaches under one of the steering column base bracket bolts.








This is the connector at the HSS control module.

Let me know what else you need to see and I'll do my best to help.


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## Trey Fisher (Nov 11, 2020)

Your pictures are very helpful. Is this the black box you have pictured? I have family stuff happening right now but I have a few more questions and pictures to post here shortly. I apologize if this has become a nuisance and/or redundant at this point. It’s hard working behind someone and trying to figure out why they did what they did and how to correct it. Also, I was able to find a spare pigtail and run wires to the FNR switch, but I’m missing a matching pigtail. I have an old one I plan to wire correctly, but this as far as I have gotten as of now.


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## Trey Fisher (Nov 11, 2020)

My main problem is still figuring out how to connect the control module to the FNR switch without the black box as it seems mine has been “deleted”.


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## Trey Fisher (Nov 11, 2020)

This is the current view


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## Keith Davis (Dec 1, 2020)

No problem on the bothering for info, as long as you can put up with my sporadic response times!

OK, so the "black box" I am referring to is here:








It is item #36 on the parts drawing








As well as it is still available from CNHi at their gold and platinum plated prices.

Your pictures appear to be of just a relay of some kind. Because the service manual does not even give this device a name, as well as the parts catalog just calls it a wire harness, thus my calling it a black box - for I cannot find any information as to what is going on inside this weather-sealed electrical component.


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## Keith Davis (Dec 1, 2020)

As for how to wire this up without the "black box"- I cannot come up with how to keep the mode command switch (turtle-rabbit switch on dash) but to by-pass the black box and that switch: connect the 12V power wire- white w/blue tracer directly to the black w/red tracer going to the F-N-R switch. This will put 12V to the F-N-R switch to send power through the black w/yellow or blue w/green wires (depending on the F-N-R switch position) to the control module. I believe that based on the service manual if the mode command switch is in the turtle position- there is no continuity through the switch, so the "black box" routes 12V to the brown w/yellow tracer wire and blue w/red tracer wires. So actually, connect the white w/blue to both. Then when the mode command switch is in the rabbit position - power goes from the switch through the blue wire directly to the control module and takes away the "time delay" engagement of the shuttle clutch.

Hopefully writing that out helps you some.


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## Keith Davis (Dec 1, 2020)

Oh, almost forgot - I have no idea what that 3-wire connector is in your pictures of your control module. Mine does not have anything connected to that plug on the control module.


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## Keith Davis (Dec 1, 2020)

I've not been on this site in a while but I see that Trey has not responded yet either. Anyway, I have my 2120 back together and moving on its own power again, so if you need pictures of the harness installed in the tractor, let me know and I'll get some. Likewise, if you need more help figuring out what wire goes where.


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## maxmax (Aug 3, 2021)




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## grcutter (1 mo ago)

Hi All,
I know that this is a very old post but I wanted to provide some information about the 'black box' for completeness and in case others have this same issue.
The 'black box' is called an Amperage Controller. It is a pair of resistors that shunt off some current from the Forward and Reverse signal wires.
See attachment.


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