The best I can do is report a couple of issues I had that may give you some ideas.
A few years ago I got a spark and smoke out of my front unit and it stopped working. Turns out one of the wire nuts connecting it to power must have not been put on tightly, got hot, melted and caused a short. So it might be possible one of yours could have "jiggled" loose but you were saved the fireworks. On mine, the electrical connection is in a junction box accessible when you take the filter out of the grill.
Last year my compressor would run, but the fan would not run unless I gave it a quick spin to get it started. This pointed to the capacitor. On mine there were two and I replaced them both and it works fine now. So you could also have a capacitor problem.
Could also be the thermostat or its wiring come loose, but I've never had to deal with that.
Good luck!