I have a 2012 kw T 800. There was no air going the the air bag leveler then suddenly started working . Where are the valves located that supplies air to the air bag leveler valve . Could it also be the dump valve in csn not working ?
It could be the dump valve but if you are in below 30 degree weather I would suspect frost in the line or leveling control valve. the air dryer cannot remove all moisture from your system (especially if the filter is more than 9 months old) and may put moisture into the air tanks. Always drain your tanks when you can park for the night in weather above 40 degrees.