Here are some more pics to go along with the manual.
I myself would start trouble shooting what you are describing of having the compressor run but no fan in this order. You need to take all the electrical wiring precautions to do these tests. If you do not feel up to them, stop. You are proceeding at your own risk. OK now past that here goes.
Take the inside plastic intake cover off that has the foam filter in it. Above this is a metal electrical enclosure with a small lid. Turn the 120 VAC breaker off to the AC unit. It should be a 20 amp in your breaker box.
The control board also uses 12 VDC from the battery. Unhook the battery or pull the fuse if you can find the right one. Now that box should be is totally dead. Test for voltage as needed.
Take the metal cover off. Odds are high just that little cover you are not going to see much other then the 3 amp fuse and a part of the board. Looks like this
So I took the entire shroud off and unscrewed the box to hang out so I can work on it. Now looks like this
Here is a close up of the board itself
Here is the wiring diagram on the board
You now have 2 options of what to check 1st. The relays that turn on the fan or the fan itself.
I'm going to just start with the fan relay on the board. Get a 120 VAC test light. Any kind of light bulb with a cord etc. A shop light, even and old lamp. Do not need much more then a 25 to 60 watt light bulb.
You will need test leads with alligator clips on the end OR strip the wires on the lamp cord etc.
Unplug the fan lo (red) and the fan hi (black) wires off the board. Let them hang and make sure they do not touch anything. Tape if needed.
Look for the white AC neutral coming in on the piece or romex wire. Put 1 lead of the 120 VAC test light on the common. Then using an alligator clip put the other lead of the test light on the Hi or the Lo spade on the control board. Make sure no hot wire is touching ground etc.
Turn on the 12 volt battery, then flip on the 120 AC breaker. Turn on the T stat so the unit will run. The compressor should start as you said it already did. The light should turn on for what ever hi or lo relay you clipped to. Try the fan lo/hi switch on the T stat. The light should go on and off with that switch.
If the light works, then you have a fan motor problem. If the light does not work, then you have a fan relay problem or the control board running the relay.
I'm going to assume the board worked and the light came on. This means you have a problem with the fan up on the roof unit.
Before you tear into the roof unit if you want to try and jumper the motor to run here is one method.
Turn off the 120 AC breaker to the unit. Unplug the hi and or lo fan wire on the board. With a alligator jumper, jump the hot 120 VAC incoming black wire, I used the black wire on the compressor relay as it was easier then taking off the wire nuts. Then jump direct to the hanging red hi fan wire. Like this
When you turn on the breaker, it will allow 120 VAC to go right to the fan motor. If it does not run, then there for sure is a problem on the roof unit.
OK now up to the roof unit. Take the big shroud off. You said you spun the motor so you where this far already. Turn the 120 AC breaker off so there is no power.
Looks like this
On front right side is the capacitor box. You can see it here. There is also a wiring diag on the cover.
And a warning label as they are capacitors inside
Inside is the compressor and the fan motor start capacitors
Here is the compressor one I was testing with my old analog meter
It broke loose inside. Maybe vibration etc.
Here is the fan start capacitor
In the pics one is silver and the other was white. I have/had 2 campers and the fan start capacitor was different. If you have an analog meter you can test them. Follow the Dometic manual.
There should also be an ohm check in the manual for a dead motor or at least an open winding. Your digital ohm meter can check for an open winding.
Odds are high it may be a capacitor, a loose wire. Last resort is the motor itself. The motor is like $130 to $165 IIRC. I bought one about 2 years ago. Bigger problem with the motor is you need to tear 90% of the roof unit apart to put the motor in. Have pics of that too.
Write down all the model and serial numbers of the AC unit. There are inside up by that control box. You can buy all the parts on line if you have no dealer nearby. PPL Motorhomes web site has an exploded parts diagram you can buy most any part. I have bought some from them.
Good luck, take pics so you remember and need to ask more questions and we can see what you are up against.
Hope this helps and stay cool... Suppose to be 104 F here on Saturday. Man, it is hot out...