RV Repair: Duo-Therm AC, fifth wheel trailer, duo therm ac

Question
I have a Duo-Therm AC unit, Model # 59516.603 (it is a duct system) in my fifth wheel trailer. The compressor work's but will freeze up because the fan motor on the roof will not come on. I have checked the capacitor and it checks OK. Could the board be bad? If so, is there a way to check that?

Thanks

Answer
Hi Rick:

If you have not already done so, be sure power is turned off completely, remove the cover on the a/c, and turn the shaft on the motor and check to see if it turning freely, or if it is hard to turn with resistance.  If it is hard to turn, the bearning are seizing up. The bearing generally are not make where they can be oiled. If ok, turn power back on, turn system to cool position, let run for a couple of minutes, then shut off power, and feel the motor. If it feels warm, then it has power going to it. If not warm, then you will need to test for power going to the fan motor. If you discover the motor bearing are defective, the motor will have to be replaced.

If I can further assist you, please let me know.

Regards, Larry