Verify the control board is giving the 120 volts the motor needs. Remove the motor wire connected to the Heat terminal on the control board and the motor wire to the neutral terminal on the control board. Then call for heat and measure the AC voltage between the Heat and neutral terminal on the control board. I would expect you should get 120 volts at the t+50 time when the relay closes. If there is voltage, then we go for the motor. There's an easy test.