[carlosalba]

I am going to replace the solenoid valves on the manual air leveling system. I have purchased the valves, 12 total. There are six in the front and six in the back. I’m wanting to know how they work before I remove them. What l can tell, two are exhaust and two let air in. The other two I’m not sure. There are two of a different style not sure about them also. Does anyone have any information about this? Wiring Schematic or how they are piped in?

Before you pull them out, it helps to label everything and take photos. On most manual air leveling systems, the solenoids are usually split between supply (fill) valves and exhaust (dump) valves. The extra ones that look different are often isolation or check-style solenoids that prevent air from back-feeding between circuits or keep pressure when the system is off.
Air typically comes from the tank → through a supply solenoid → into the air springs, and exhaust solenoids vent air to atmosphere. Front and rear are usually mirrored but plumbed separately. Wiring is often simple: switched 12V with a common ground, each solenoid energized individually by the control panel.
If you can’t find a schematic, a good auto repair approach is to trace the air lines one by one and verify function with low pressure before removal. Replacing one valve at a time also helps avoid confusion.