This is the A/C fan and motor. It will turn by hand, but not easily.
The starter capacitor is adjacent to the fan. Based on the unit's behavior when we apply power, she's pretty sure it's just the fan motor that's failed. If we can find a replacement to get the air blowing again, we might even be able to have the original motor rebuilt, as there are places in in the Sparks industrial district who rebuild electric motors.
Getting a replacement fan is the problem. As the folks at the local RV parts sources told us, parts (and air conditioners) are badly back-ordered. They take it for granted that all parts and all new air conditioners are exclusively made in China ("Everything is made in China") and there are huge delays due to the pandemic and the Trumpy Trade War. Dometic, the company that manufactured the air conditioner, has the official replacement, which is indeed Chinese; however, the original fan motor was made in Mexico, and we figured out the OEM, even though the company has since been bought by a different one. Even so, that part is shown as back-ordered/out-of-stock everywhere we've found it online. However, we did locate what seems to be a replacement motor ("installed but never used") and if we can confirm that it's the actual OEM part, we'll order it. Unfortunately, it will take at least a week to get here, and that's making life difficult. The only think helping right now is that thanks to afternoon thunderstorms every day for the past several, the temperatures are slightly less hot (highs around 35°C instead of 40° still aren't what you'd call "cool") than they were the week before, and when the clouds blow away, it cools down into the mid-to-high teens overnight. If we hadn't built the shelter over the trailer, it would be an outright oven right now. Keeping it in shade all day long means a great deal.
This afternoon we bought several additional box fans, after one of those we already had also broke down. Lisa thinks that in this case it's the switch, not the motor, and may try to repair it someday, but we needed more fans now, not later.