I serviced this NordicTrack GX 2.5 Upright Cycle in Somersworth, New Hampshire.
Problem: The resistance stayed on high and could not be changed.
The bike needed to have the resistance motor replaced. Not because the motor did not work, but because the cable mount on the side of the motor housing was broken off. Because of this the cable did not work properly allowing the user to change the resistance. So while the control panel indicated that the resistance was changing and you could hear the motor moving, the resistance did not change.
Solution: The resistance motor, NordicTrack P/N: 193223 needed to be replaced.