Mine are going strong for 2+ years now and have seen lots of snow and frost. Initially I had the same concerns, so here's the reply I received from George over at Amp.
"If the linkages have never been power washed then I would do this. Open the door and step on the board with one foot and apply pressure to the board while at the same time close the door. This will keep the steps down with the doors closed. Now cover the motor and gear box with a plastic grocery bag to keep the high pressure water from getting in as these are not submersible motors. Next, power wash the linkages concentrating on the sides of the linkages where the pins enter the bushings. Once you have cleaned them well if you have compressed air blow them out otherwise let them air dry and concentrating on the area where the pins enter the bushings, lube them well with Silicone spray lube only, no grease, oil or WD-40 as they will attract more dirt and debris. Also spray the entire outside of the linkages making sure to not spray the boards as Silicone is very slippery. For where you live this is the ticket. At least once a season you will need to do this due to the salt, sand and chemicals used on the roads builds up over time in the bushings and tightens the linkages. And because the system uses amp draw to shut itself off, if the linkages become tight the system will stop short of full retraction. If this does not cure the problem then give me a call and we can go over the issue in detail"
Gotta say, works like a charm. The couple of times that they wouldn't lower was due allowing a crazy amount of slush to freeze between the steps and body. Which is why I never leave home without a rubber mallet, lol.
