From the WSM:-
The sensor is supplied with a reference voltage from the air suspension control module which
measures the returned voltage to determine the sensor arm position. On the front height sensors the voltage
decreases as the vehicle height increases. On the rear sensors the voltage increases as the vehicle height
increases.
The sensors can be checked by applying 5V across the positive and negative terminals and measuring output
signal which should be a nominal 57mV ± 3% per degree of sensor arm movement.
The following graph shows the vehicle height displacement from normal against output voltage for the front
height sensors. The (blue) center line represents the "nominal" condition but depending on tolerances, the
actual line may lie anywhere between the (green) upper and (red) lower lines.
Front Height Sensor
The following graph shows the vehicle height displacement from normal against output voltage for the rear
height sensors. The (blue) center line represents the "nominal" condition but depending on tolerances, the
actual line may lie anywhere between the (green) upper and (red) lower lines.
Now I've looked at that, I'm wondering if the 5V & the output lines have been mixed up (or as suggested, it's a rear sensor) Did you check the wiring by colour or by voltage? there can be close to 5V at the wire which should be on the output when open circuit.
Ignore my comment regarding Hall effect sensors, that's not the case given your observations.