Here is a small blessing - zippers. Elias Howe, in 1851, patented an Automatic, Continuous Clothing Closure similar to a zipper. Today they are ubiquitous and we take them entirely for granted until they jam. I bought a kit some years ago for mending zippers. It included an instruction book on common causes of zipper problem and how to fix them. The remedy is often quite simple.
Fixing things depends on having an accurate mental model of how they work and the ability to observe. My brother also taught me two more axioms of fixing things. One was the rule of screws: "Righty tighty, lefty loosey!" and the other was, "Assembly is the reverse of disassembly." In other words, take note of the order in which you take things apart and keeps the bits separate. These axioms don't apply to zippers, but they are useful to bear in mind.
So next time the cold wind bites, operate your automatic, continuous clothing closer and think of Mr. Howe.