Last fall my 2008's AC started only working on high, if at all.

I ordered what a replacement resistor (weather got cooler, so I got lazy), but it looks like they sent me the resistor for the GE.

It won't fit in the hole that the old resistor came out of, but the connector is the same and it "fixes" the problem.

It's breaking 100 here every day, so I'm thinking about putting the old resistor back in the hole so air flow isn't disrupted, but connecting the new resistor and zip tying it in place until I can get the correct part.

Perhaps a dumb question, but will the back of the resistor being exposed (i.e. not in the blower tube) be any danger? fire, shock or otherwise?

 

You got the transistor.
Resistor and transistor are different in size, thats why they dont match.
Still the reason for this to be in that hole is because the air will COOL it.
Both of them should be fixed inside that hole.
You could make the hole bigger, exactly to match the whole metallic plate to be inside, and use screws to fix it, or some tape.

If you don't do so, the risk of fire is quite high.....