I had a customer a few years ago that used reach trucks in a deep freezer but would then charge them outside on the loading dock. Needless to say, in Houston heat and humidity, the trucks would be sitting in a lake in less than 30 minutes. The onlt thing that worked was spraying all circuit boards with Corrosion Block (I think it was made by Certified Labs) and coating the connections with dielectric grease. No more problems after that.