I have an old rental mobile and the heat pump is operating normally, except the outdoor unit fan is running all the time (unless the breaker is off), and it runs very slowly. The run capacitor measures 28uf versus parts websites showing 35uf.
I might believe that might cause the slow problem, but not the "all the time" problem. The schematic shows a one speed fan, so I don't think it's confused about what it should do. Also, the schematic shows the "run" capacitor wired as a start capacitor for the compressor. The "start" capacitor shows being the start cap for the fan.
I did replace the wiring harnesses in the indoor unit a few weeks ago as they had developed an intermittant and melted everything. It's a 3500A912 unit with a 5871 adapter. If I need a new heat pump, I'll scrap the mobile. Unfortunately, I just spent a couple $K doing ceilings and carpet.