A couple of days ago I received my air solenoids for the suspension system. These are electric actuated pressure valves are used to connect two airbags and equalise the pressure. They have a pressure input and a NC and NO output. 12V operated they are driven by a microprocessor and a local switch. The purpose is to make sure both airbags on one side have the same pressure while the air level system lifts the van to the pre programmed position. Because the wheels in a closed coupled system are so close together the height sensor on one wheel will fool the control unit about the height/pressure in both bags. Height alone is not an indication of proper lifted bags. The Smartride system is not that smart afterall and only allow height control or pressure control but not both together. So for the time being I use these valves to connect the airbags when levelling and also when I want to run the suspension load shared. Later on I will replace the smart ride system with my own control unit allowing both pressure and height monitoring in combination with a tilt sensor. Calibrating the height sensor at the moment is manual and requires level ground and a manually levelled chassis.
One of the reasons the Smartride system is not that crash hot on the van is the fact that it was developed for the hot rod market and usually the sensors are connected to the wheels on 4 corners of the vehicle. This makes operation on independent bags more precise. Two bags very close will never be really controlled properly by height only. One wants the pressure in both bags to be similar and the heights of both height sensors should be similar too. This is what my own system will achieve eventually.