Ford/New Holland 2120 w/EHSS. Does anyone know what the Amperage Controller box does?

[grcutter]

I have a 2001 Ford/New Holland 2120 with EHSS that is giving me intermittent neutral problems.
I have traced all the wiring and came across a mysterious small black plastic box that is in between the shuttle shifting switch and the EHSS controller box.
I can not find this box on any schematic that I have but I did find it on the parts diagram.
It is part number 36 on this diagram: New Holland 212 - 4 CYL COMPACT TRACTOR 2 SERIES(1/87 - 12/2) Parts Diagrams
A search of the web says that it is an "Amperage Controller".
The part number is 47837495 and the original part number is SBA385870820.

Does anyone know what this box does and how to test it to see if it is still good?

 

[grcutter]

I put together a few figures that illustrate the part physical location and it's location on the schematic if it helps anyone to identify it's function and figure out how to test it.



Thanks in advance.

 

[kirkawilson]

I tried to upload the a couple of 2120 EHSS maintenance manual cut sheets that I found on the TBN forums but neither the standard or advanced attachment picks are working for me right now. I think JimmySisson posted the cut sheets but he has not been on the forum in a while. But it appears that you already have them from your posted figures. The 'amperage controller' title seems to indicate it might be have an amp limiting function for safety?

The only other tidbit that I read in TBN is that a diode in the EHSS controller box has been a failure point.

 

[the old grind]

Even factory manuals of different years printed may not show updates 100% or may not edit details completely between part # lists, text, & pics when revised. (I have such, all NH Shibaura) I & T FO-46 only shows schematic for 2120 gear vs shuttle, so no help there.

Second pic seems to show the piece bridging vs replacing a 4-prong connection or bit of wire, say as if added later in response to switch failure in early models. I suspect a current limiting diode might be an update that just isn't represented where we seek it. Connecting wouldn't match the pics.

Got a pic of the placement and where it connects? Diodes are typically tested with a VOM for current flow. (HFT <$10, etc.) Function may be as simple but form-factor may disguise more than a single component within, but the test should be valid either way. There rare exceptions to that but moot if the part tests ok.

It's on a common line thru' the switch and going to the shift control valve. It could be there so soften inrush current for its sake when switching modes. btw a zener diode might be used to limit voltage but amperage was mentioned. That and using a diode to limit current is just new to me.

 

[grcutter]

A local New Holland dealer helped me obtain the tech sheet on this part. It appears to be a pair of 240 Ohm resistors to ground from the Forward and Reverse signal wires.
For reference, and in case it helps someone else, I have put together this tech sheet and the pictures in this attachment.
View attachment Amperage Controller.pdf

 

[fried1765]

A local New Holland dealer helped me obtain the tech sheet on this part. It appears to be a pair of 240 Ohm resistors to ground from the Forward and Reverse signal wires.
For reference, and in case it helps someone else, I have put together this tech sheet and the pictures in this attachment.
View attachment 684350

I wonder if that is the same setup on my 1920 with SS?

 

[grcutter]

I wonder if that is the same setup on my 1920 with SS?

Not all of the 2120's had this Amperage Controller. Mine is from 2000 which is the last year that they were manufactured (I think).
I think that this may have been a late adder to correct some problem as it is not well documented and does not appear in the regular service manual or supplements.
With regards to your 1920, you can open the panel below the instrument cluster and look for this part or the absence of this part by following the wires from the shifter.

 

[fried1765]

Not all of the 2120's had this Amperage Controller. Mine is from 2000 which is the last year that they were manufactured (I think).
I think that this may have been a late adder to correct some problem as it is not well documented and does not appear in the regular service manual or supplements.
With regards to your 1920, you can open the panel below the instrument cluster and look for this part or the absence of this part by following the wires from the shifter.

Thanks!
My 1920 was built in 1989, so it would seem not likely.

 

[billfires]

fried1765, I think that is probably specific to the EHSS on the 2120. Our 1920 is a mechanical Shuttle Shift. Bill C