I just spoke to HWH and asked this question.
I have a HWH 325 system in my 2005 Suncruiser. My level sensor and leveling light adjustment is located at the bottom of the control box behind the front driver's side wheel. The control box has a clear plastic window on it. Remove the window and the sensor and sdjustment is in the bottom of this box.
I'm quoting HWH's 325 service manual below.
The sensing unit is located in the control box. There are four yellow LED's on the sensing unit.
These LED's will match the yellow Level Sensing lights on the touch panel. With the vehicle level all of the lights on the sensing unit and the touch panel should be out. If one or two lights are on, adjust the sensing unit according to the SENSING UNIT ADJUSTMENT page in the diagram section. It is important to note that very small movements of the adjusting nut or screw should be all that is needed to change the yellow LED's on the sensing unit. Use the jacks to raise one side or end of the vehicle at a time to make sure each yellow Level light will come on and go back out.
The sensing unit LED's can be checked with just the ignition on. The Level Sensing lights on the touch panel can only be checked if the LEVEL MODE light is on.
SENSING UNIT ADJUSTMENT
Level the vehicle by placing a bubble level in the center of the freezer floor or upon whichever surface within the vehicle that is to be level. Using the Leveling System and the bubble level, ignoring the yellow LEVEL lights on the Touch Panel, level the vehicle until the bubble is centered.
When the vehicle is level according to the bubble level, if there are no yellow lights lit on the Touch Panel, the sensing unit is properly adjusted.
If there are yellow LEVEL lights lit on the Touch Panel, manual adjustments to the Sensing Unit are needed. A 7/8" or 3/4" socket w/driver and a philips screw driver will be needed.
The Sensing Unit is mounted inside the Control Box. The Control Box is mounted to the power unit/valve assembly.
There are four LED's on the Sensing Unit, A,B,C and D. Refer to the drawing below. The Sensing Unit is adjusted by turning the adjustment nut to turn out LED's B and D. The adjustment
screw will turn out LED's A and C. If the adjustment nut has to be turned more than 1/2 flat or the adjustment screw has to be turned more than 1/4 turn to turn the LED out, there may be a problem with the Sensing Unit or the mounting of the Control Box. If two LED's are on, either adjustment may be made first.
For more information I suggest you get HWH 325 Service Manual at:
If you do not have the 325 system select the service manual for your system at: