To begin with, check the "ride level" fuse and make sure that the ride level compressor does work, and you should be able to hear that the ride level compressor is working when the ride level system is leveling the vehicle
The ride level system uses an air compressor and either an air type of shocks or a type of air billow to raise and lower the vehicle, there is an adjustment to set the ride height and it is located under the vehicle and there is a control lever or rod that should be connected between the rear axle and a switch that is mounted on the body of the vehicle, and there will be an adjustment slot in the control lever between the switch and the body, and that is how you would adjust the ride level height, but be sure that the vehicle can not drop any further down if someone is under the vehicle trying to adjust the ride height.
However, you might find that the control lever to the ride level has fallen off from the switch on the body or it has come loose from the rear axle, and it is just hanging
there not operating the switch on the body that controls the the ride level compressor, or there might be a blown out air shock or billow, or you might find that an air line from the compressor is leaking and the ride level compressor will just run continuously
until it blows out the fuse, and if that is the case you might also find out that the air compressor has burned out from