#1 - You have a leak that needs to be fixed. This is intended to be a closed system (filled with nitrogen to overcome issues with moisture/temp changes), but it employs a supplemental AMBIENT (see: moisture-filled) air intake to "limp" you around if you have a small leak somewhere. Unfortunately, once your closed system has become filled with ambient air, the moisture apparently wreaks havoc on lines, valves, etc in freezing temperatures.
#2 - A bit of air line anti-freeze into the intake hose (behind passenger side headlight...the line with the filter on it) every so often during the winters seems to be a highly effective and recommended band-aid for future freeze-up problems.
I just bought a '15 Rebel trade-in from a local dealership. I was supposed to take delivery almost 3 weeks ago, but instead am still waiting for them to fix the air suspension in it after I noticed a blown 40A fuse sitting under the hood, and then popped by the dealership later that evening to see the front end sitting on its bump stops. I would have simply walked away from the deal; but it's a REALLY good price, super low miles, and the dealership's been great about making it right before I take it home. They've replaced the valve block and now the compressor (and also put a brand new set of K02's on it when the tires didn't pass safety). Now it's sitting for the weekend with the fuse(s) pulled to see if it holds air as it should. They're also giving me a 12 month warranty at no additional charge, in case I have issues in the upcoming Winter. During this time, I've been doing a LOT of reading on the topic and learned a ton about it. The air line anti-freeze tip seems to be a pretty dependable move to prevent future freeze-ups, but remember that if your system is pulling in ambient air for any reason, then you're losing air somewhere and need to rectify that problem sooner than later.
