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Discussion Starter #1
I'm trying to get my auto header height to work on my combine. And I don't know if i'm just not setting it up properly or if its not working or what I'm doing really. I only have one season on the combine so I'm still learning it. Just picked up a 74c header this spring, and have never had a straight cut header before so learning it as well.

I put the header on and I can set my stubble height and max height fine. But when I drive along and put one side of the header along my ditch so it touches the ground the header will not raise at all. Am I mistaken or if it has the sensors on it should it not follow the contours of the ground like a pick up header would?

I've done a header calibration. I've selected my header type (tried draper and grain not sure which one to use). I don't know what else to do. What am I missing or forgetting?

Also, how do you choose between autofloat and stubble height? sometimes the combine does one and sometimes the other and I'm not understanding how it selects it or if I can make it do one or the other?
 

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OK. FIrst, lets start with the FUN part---the combine selects which height mode to be in--and you have NO control over that. (Brilliant, right??).

As far as making this work, I assume you are operating this in FLEX mode, not off ground rigid mode. There is one minor difference that must be dealt with, but for now I'm going to assume Flex.

The next problem we need to clear up....in 2008/2009 NH switched from a 10V Bosch AHC system to a 5V CNH AHC system. The two are not compatible. It is possible that your header is set up with the 5V sensors, not the Bosch 10V sensors. Not real common, but I have seen it.

SO the first step is to look at the sensor voltages. GO to the Header Diagnostics page on the monitor, and look at the Left & Right Stubble Height sensors while moving the head both fully up & fully down. They must always be -
  • Greater than 2.5V.
  • Less than 7.5V
  • change more than 2.5V.
  • Note that the sensors swing "opposite" each other -- when down on the ground the Left sensor should be 2.6-3V, the Right sensor 7-7.4V
If your sensors are working properly set your combine header settings like so:
Grain, Flex, AutoFloat = Installed

Then redo the ground calibration. When "succesfully completed",
  • lower the head fully to the ground, then raise the frame 2-3" from fully down (leave the cutterbar almost fully compressed.)
  • Start the Header & Thresher
  • Set the Height select switch to #1
  • Press and hold Resume ~2 seconds (should beep)
  • Look at the run screen. You should have a header icon with a wavy line under it.
  • If so, then use the +/- button to nudge it up to the float height you want (flex cutterbar must still be on the ground). Recheck Icon.
  • Should now perform correctly.
If you have a straight line under the head, that is RTC mode, and its not AHHC.
 

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Discussion Starter #3
I checked the value out and they are within spec I beleive. Left was about 3.5v and right was 5.7v. I am not doing it in flex mode so maybe that's different then? I was assuming that when not in flex mode when the sides or something would get bumped by the ground that it would activate. But doesn't seem to be the case. There is a straight line under my header icon.

Dont really have time to play with it today but will try find some time tommorow to try it out again.
 

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Nope. AHC won't work when not running down in flex mode with the "wavy line" icon.
 

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Discussion Starter #5
Oh ic ok. So there no auto header when straightcutting wheat or something say? Unless I run the header on the ground?
 
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