1) The low air light should not be coming on at 90 psi. 2) The engine air compressor (I presume the engine was running when you were witnessing this phenomenon) should kick in WAY before the pressure gets down to 90 psi. With the engine running, the engine air compressor should hold the air pressure between about 105 and 125 psi. With the engine off and the 120 volt air compressor on, the air pressure should be between 75 and 90 (although these points can be adjusted on some compressors). When driving down the road, the air suspension will cause the pressure to drop. When stationary, the system pressure should hold for a minimum of 40 minutes before the air compressor cycles (Newell's standard). If you have gone through the coach and located and corrected the leaks, it should hold for hours. Note: if the brake air is going down with the system air pressure with the engine running and not hitting the brakes, you have a serious safety issue and you need to replace the air brake check valves and determine if there are any leaks in the brake system that need to be addressed. Losing brake air can ruin you entire afternoon when the rear brakes lock up at 60 psi.
However, based on the low air light coming on at very high pressure readings, I would go with Forest's answer. The pressure switch could be bad or you could have a bad connection.
|