300 SERIES: 191994-1996
This is a touch panel controlled manual air leveling system. It was supplied as just a PC board or as a 14.5″ x 9.0″ x 4.0″ control box. The touch panel will have “HWH AIR LEVELING” printed across the top of the touch panel. It was used on a 3 and 4 point air leveling systems. The 3 and 4 point touch panels look identical so the only way to determine the correct touch panel or control box is to locate the control box/PC board and get the AP part number or look at the front HWH air manifold. The front air manifold for the 3 point system will have 3 air solenoid valves and the 4 point system will have 6 air solenoid valves.

WARNING: BLOCK FRAME AND TIRE SECURELY BEFORE CRAWLING UNDER VEHICLE. DO NOT USE AIR SUSPENSION TO SUPPORT VEHICLE WHILE UNDER VEHICLE. VEHICLE MAY DROP AND OR MOVE FORWARD OR BACKWARD WITHOUT WARNING CAUSING INJURY OR DEATH.

300 Series PC Booard

300 Series Control Box

300 Series Touch Panel

3-Point Front Air Leveling Manifold

4-Point Front Air Leveling Manifold

310 SERIES: 1994 – 2004
The 310 system is a manually controlled leveling system. Most systems are touch panel controlled and work with straight-acting or kick-down jacks. There is a 3-jack system that is controlled with a rocker switch panel. That system has no level sensing unit. There are motorized and non-motorized 310 systems. Most 310 series control boxes are a 4.25" x 2.75" x 7.0" metal box. There is a 310, non-motorized 6-jack system with a 14.5" x 9.0" x 4.0" metal box. Most 310 non-motorized systems use a touch panel that is part of a pendant assembly. The touch panel connections for these control boxes look different that the motorized control boxes. 310 touch panels have "HWH HYDRAULIC LEVELING" printed across the top and have a "NOT IN PARK/BRAKE" light. Note the connector arrangement on the back of the touch panel. This system can be used with a spring suspension or air suspension. There were special touch panels for suspensions using pilot air dump.

Note: There are several touch panels for non-motorized vehicles that look identical. You may need to get a control box AP part number to get the correct touch panel.

310 Series Control Box Motorized Vehicles	310 Series 6-Jack Control Box Non-Motorized Vehicles
310 Series Touch Panel No Air Dump	310 Series Touch Panel With Air Dump
310 Series Touch Panel With Pilot Air Dump	310 Series 3-Jack Rocker Switch Panel
310 Series Pendant Non-Motorized Leveling	310 Series Pendant 2-Jack Stabilizing

305/325 SERIES (Short Board): 2004 – 2005
The 305/325 system is a touch panel controlled manual hydraulic leveling system. It was only used with motorized vehicles. The control box is an 8.5" x 11.5" x 3.0" metal box with a clear Plexiglas cover. The box PC board was only about half as tall as the box. The 305 Short Board system was NOT equipped with a level sensing unit. The 325 Short Board system was equipped with a sensing unit. The main identifying features of the touch panel are "HWH HYDRAULIC LEVELING" printed at the top of the touch panel and there is no "NOT IN PARK/BRAKE" light on the panel. This system was only used with straight-acting jacks.

305 Control Box No Sensing Unit	325 Control Box With Sensing Unit
305/325 Touch Panel	Touch Panel Connections

325A SERIES (Long Board): 2005 – 2007
The 325A system is a touch panel controlled manual hydraulic leveling system. It was used with motorized and non-motorized vehicles. The control box is an 8.5" x 11.5" x 3.0" metal box with a clear Plexiglas cover. The PC board is as tall as the box. The box is normally mounted on a pump assembly bracket. The touch panel has "HWH HYDRAULIC LEVELING" printed at the top of the panel and there is a "NOT IN PARK/BRAKE" light on the panel. This system was used with straight-acting or kick-down jacks. The front of the touch panel looks the same as the 310 series touch panel. The difference is the connectors on the back of the panel. The 325A touch panel only has one connector. The panel for non-motorized vehicles has no "Not In Park/Brake" light and is also available as a pendent control.

The 325A system was available with a touch panel that did not have an "On" button. It was referred to as the 325S system. This system could be converted to fully automatic fairly easily.

325A Series Control Box	325A Series Touch Panel No Air Dump
325A Series Touch Panel With Air Dump	325S Series Touch Panel No Air Dump
325A Pendant Control Non-Motorized Touch Panel Does Not Have "NOT IN PARK/BRAKE" Light