I'm on the opposite side of the country for you otherwise I'd be happy to put the Nano on to check for you. You can check the blend motors manually though. With the engine warm, put both sides on 20C and check that air out of both sides is the same temperature (there may be a slight difference but not by much), then change one side to Hi and confirm it changes on that side, change it to Lo and check again. Then put that side back to 20C and repeat the same test on the other side. If the temperature changes on both sides as you expect it to, then try changing where the air is going and confirm that when set to windscreen it blows on the windscreen and so on. A good final test it to poke the Prog button. That should turn on the front and rear screen heaters, put the fans on high speed, both sides on Hi (hot), engage the AC compressor and direct the airflow to the screen.
If either side doesn't change temperature when you tell it to, then there is a problem with that blend motor. When you first turn on the ignition, they are driven from one end of their travel to the other and the feedback from each motor is checked to confirm it is doing what it should do. There are two problems that affect them. Either the flaps that the blend motor move have seized so the motors stall, or the feedback pots inside them have worn out so the HEVAC doesn't see the movement. First though, identify what the problem is. Bear in mind that if the HEVAC detects a fault with one motor in the self test, it will not try to move that motor again. Sods law says that if a motor sticks at one end of the travel or the other it will invariably stick at full hot in summer and full cold in winter!
Admittedly with the Nanocom you can drive the motors from one end of the travel to the other and monitor the feedback but that still doesn't tell you if the motor is moving and there is no feedback or if it isn't moving. In both cases, you need to get a few panels off so you can see the motors and check if they are actually moving or not.