Join Date: Dec 2009
Location: Out there, somewhere
You may WANT to use one jack, just because a single corner is low but, the HWH systems, either manual or, automatic, doesn't look leveling just one corner in its operational characteristics. As you stated, and, in the Automatic mode, when you push a the "left" side button, it will extend TWO jacks, on the left side. Same for the right side. Now, obviously if you have air suspension, both manual and automatic operations require the depletion of the air in the bags.
Once the bags are depleted, then leveling operations can begin. What basically happens is this. When you ask for the extension of say, your left side jacks, the controls will extend BOTH jacks on the left side, simultaneously. It's designed to do that. But, when the higher ground jack, comes in contact with the ground but, the lower ground jack, (as in your case) still has to travel to come in contact with the ground, the earlier one will just sit there, 'till, both jacks have equal pressure.
Then, they will both travel until you let off the button. Now, you then push the low "end" button. The same thing will happen. It will extend the jacks on one end of the coach, one of which is already down and in contact with the ground. But, the other one, will travel downwards 'till it hits the ground. At that point, they both will continue to extend until you let off the button.
Now, it (the system) has no idea that you're low only on one corner. It simply supplies pressure to BOTH side jacks the same time, based on equal pressure. It's then up to you to raise the rear enough to achieve the amount of level, to match the side that's already up. Sometimes it takes a few push's of the buttons to get things to end up the way you want, in the manual mode.
Now, if done somewhat correctly, you've basically leveled the coach, manually. But, you've sill got one jack up. You then extend the other end or, other side and, that remaining jack will extend.
In the automatic mode, the system operated exactly as I just explained it only, it will extend that last jack, until it makes contact with the ground and, then, it will raise the coach approximately 3/4" - 1" and, shut the system down completely.
But, my point is, #1, you cannot just lower one jack. The problem with that is, and it's really obvious, you could tweak that frame and or, cause damage to potentially multiple components, including the frame, body, windshield, etc.
As stated, the system is designed to lower two at a time, as you've noted, front two, rear two, left or right two.
I certainly don't want to make it sound as if you're not aware of how your system works, I just want to help clarify maybe some of the reasoning on WHY it works in the manor it does. Hope this helps some.
2004 ITASCA HORIZON 36GD, 2011 GMC Sierra 1500 4x4 Toad '08 GL 1800 Gold Wing
Retired-29.5 yrs, SDFD, Ham - KI6OND
Me, Karla and the Sophie character, (mini Schnauzer)