Hi: You won't have a freeze up. When the compressor test those two lines, it is checking for blockage, my understanding is that if the system runs out of nitrogen it uses air. When air is compressed water is developed. Air contains water. This little filter prevents water droplets that fly up from the rear wheel from entering the system, but it does not filter out the vapor in the air. It will help. Every time the computer test the lines, air on the incoming line and a bit of the nitrogen to test the out going line. Eventually the nitrogen will have to be topped up as one of the messages will indicate nitrogen "LOW" on the data reader that the tech uses, but the message on the truck will simply say service air suspension. Mine went for about a year and a half before I got that message. The tech that services my truck told me a couple years ago to get the system purged before freeze up to get the water out and refill with nitrogen, but I just did not bother getting it done. If your suspension drops down, you probably have a leak. To my knowledge each wheel is independent with a sensor on each wheel. I saw the sensors on the front wheels, but I did not check the back wheels. There are six ports on the valve body, one for each wheel, one for the out line and one for the in line. If a little bit of water gets up to the valve body, it will probably cause erratic operation, but you may not get a message. I plan to change the little filter in the fall before temp drops to freezing and get the system purged and refilled with nitrogen. Hope this helps you..
