You are probably right about the climate. We (North TX) typically have only 2-3 days of “ice events” each winter lasting no more than 3-4 days each. And I never take the trailer out in one. They have started using a brine mix on the roadways in the last few years. So it may become more of an issue. Used to be they would just throw a little sand on the bridges and hills and call it a day.
Each side’s turn/brake wire is independent of the other side. So a turn signal on one side would not affect the other side. Brakes would turn on both sides.