I have a 2014 sport, air suspension. 2016 new compressor $1800.00 on warranty. It has frozen up again, that means there is water in system. Mine does not drop. I do not put it up or down in cold weather. I have been researching this for 4 years. The problem is the computer is testing the two lines behind the right tail light for blockage!!! When it test the incoming line it brings in a bit of air to test it. There is water in the air when it is compressed. It also tests the outgoing line by expelling a bit of your nitrogen. This is a closed loop system of nitrogen, however it seems that the system will use air if you lose nitrogen. They should never bring in air, period. Over time the water accumulates and when it gets cold the water freezes, maybe in the compressor, blows a 40 amp fuse or it might burn out the compressor. Dodge probably will not change the software in the computer to stop testing those lines. It is "cash cow". They wanted about $1000.00 to do a whole bunch of test. I told them that I needed the system purged to get the water out. They tested for air leak based on the diognostic, low nitrogen. There was NO air leak. The nitrogen was low because the computer keeps testing the lines for blockage, bringing in air and expelling nitrogen. I picked up the truck. They had filled the nitrogen so I don't think I will have anymore problems as they probably got some of the water out when they did that.
I had a long talk with the tech and my profession is electronic and here is what I suggest. Take the back tail light out, replace the little paper dirt filter with a throwaway dirt/water filter $5.00, I installed 1/8 hose fittings, have Dodge "PURGE the SYSTEM" and that will take out the water. Do this before you get cold weather, once a year. That will cost you a couple hours labor. Preventative Maintenance. You should be good for the winter, you won't have problems in warm weather, at lest I did not have problems.