I have a 1998 4x4 navigator. The check suspension light comes on when I drive it and the compressor comes on even when the ignition is off. It comes on repeatdly. Now, the back is sitting low and won't rise anymore. Need help, right away.

Check the fuses and or relay. If the compressor is working and you can hear it running, but the bags are not filling up, then you could have a hole in the bags or their cracked or a pinch in the line. Something along those ideas...