Well that all makes sense. Heavy load, system inflates, load is relieved, system tries to vent to get back to trim height, venting doesn't happen, system didn't trim, height sensor is not happy, check air suspension lamp illuminates and system shuts down until reset with the ignition switch being cycled.
I would bet the farm your vent solenoid is fubar or intermittently so. Mine acted the same way and sometimes it would vent, most of the time it wouldn't. The solenoid lives in an atmosphere of moisture laden air and corrosion finally gets the best of it.
Check the sensor with a meter
Procedure please. Meter type? What wires to probe. Values? Without these parameters, I don’t know how anyone could possibly test it.
BTW, the system can not be checked with the Rotunda SUPER STAR tester, but requires the Rotunda SUPER STAR II tester.
Out of range as in it could come out of a socket or been extended too far
If a height sensor socket came off of one of the balls, it would default to full length, thus simulating being too high. At that point the system vents and you experience full deflation. No need to ask me how I know, but my back is still sore from the rough ride home. That is the default, rather than turning on the compressor and burning it up.
The system would try to vent, but if the vent solenoid is inoperable it’s not going to happen.
As to vent manually you could take the solenoid out or a power to both vent solenoids one on the bag one on the compressor.
I think you have some big misconceptions about how the system actually works and it might be worth your time to curl up with a manual if you have one. All 3 solenoids (2 air
spring solenoids, and the vent solenoid) are provided B+ whenever the system is active. To energize the solenoids the B+ is taken to ground by the control module via the device coil.
To vent the system you would have to remove both air
spring solenoids, something I would not recommend.
To vent the system you would have to take both air
spring solenoids
and the vent solenoid to ground at the same time.
However, if the vent solenoid is fubar, all deals are off.
Good luck.