Replacement AC fan motor very weak.

Lazarus Alessandria wrote:
Short version: I just replaced a failed AC fan motor. Now the fan actually works BUT it runs at around 20% of the previous speed and blows air very weekly. Also, when I set the fan to auto instead of low or hi, it doesn't blow at all. Help!

Background: I've got a Dometic 13.5K BTU ducted AC in my 2014 Coachmen Apex. A while ago the fan started having a very hard time turning on (click and hum but no turning even if I tried to spin it by hand) but after trying for a couple hours if get lucky and it would start. Once it started, it would run indefinitely. I replaced the capacitor and that didn't really help. Yesterday, I got it running after a struggle and it ran for a few hours until it started squealing louder and louder until the fan geadually slowed to a stop. I got a replacement for my model (457915.711CO) from an RV service place, same size, wire colors, wire lengths and connectors so I felt confident it was the right part. I installed it and now I've got the problem I mentioned above. Could it be a bad ground? Did I swap a wire? Anything? O was only 95% sure that I put the condenser fan back on the right way but that doesn't seem like it should me such a drastic difference in the speed the motor will turn. Any help is appreciated.

Could you post your before and after photos of the wiring, we might see something you missed.
If this is one of the newer Dometic I agree that the controller possibly bad as these use a 3 wire communicating tstat/control .