Trane Mod# TWY048B100A heat pump with Var. Speed cond fan... System is colling well, its 90+ outside but the fan is ramping up to full speed then shuts down only to ramp up again. It repeats the cycle ever few seconds. I went over the wiring diagram. In the cond fan control circuit it shows an outdoor fan stat, a fan control board, the defrost control board and the motor, but doesnt explain a sequence of events, or what is actually happening inside the boards. I jumped the fan stat and replaced the fan control board with a new one... No Change... I dont want to order a replacement motor unless Im sure. Also after I left I realized that I although I had jumped the fan stat I didnt pull a wire off it and open the switch to see if this changed anything. Does anyone know how its suppose to work so I can properly troubleshoot.