I have resolved the problem with air suspension freeze up for now. I found a guy on YouTube that used a very small amount of air brake anti freeze used on trucks with air brakes. I bough a liter for 5 bucks at Parts for Trucks or NAPA and it seems to work great. You use a very very small amount. I used 1 ml with a syringe in the incoming air line behind the right tail light. It has been working great now for well over a month. I also replaced the water filter as well. I have not had my suspension purged for about 5 maybe 6 years, however I am going to purge it in the spring. After you put the anti freeze in you will need to drive the truck a bit so the fluid moves around. Once it is operating, cycle it several times to ensure the fluid gets to the freeze areas. My truck is riding a bit rough probably because there is water in the air bags taking up some of the space. I have made a procedure to purge the system that I will try later, for now it works.https://www.youtube.com/watch?v=0tcUlzDDexQ&t=1s