Yes!
I had to replace the fan in a late '60s Frigidaire Custom Deluxe (which is how I came to know that the universal kits do work) and when I plugged it back in, I had two settings (a little like a Flair oven - all on or all off).
I had inadvertently mixed up the run and heat wiring at the aftermarket defrost timer while troubleshooting.
Got that sorted out and it's been -10ºF in the freezer, 32<span style="font-size: 12pt;">ºF in the meat keeper, 34</span><span style="font-size: 12pt;">ºF in the dairy section and 35-36</span><span style="font-size: 12pt;">ºF everywhere else ever since. As intended. (And, no, I'm not interested in lectures on how that's far colder than it needs to be and I'm wasting energy. Nonsense!)</span>
<span style="font-size: 12pt;">Morale of the Story: Take lots of cell-phone pictures/video, make copious notes and if it ain't broke, don't touch it. If it is broke, assume your repair is going to lead to other complications. New wine in old skins, etc.</span>
Still prefer a vintage refrigerator to any of the modern throw-away trash.