I don't think the Techinfo method would work on a 97 (it works on my 93). If I am correct, you would need a scantool for that.
No heat situation that you describe may very well be a faulty air-mix actuator. Actually, I have the same problem right now (and the codes confirm that). I had the same problem about year and a half ago, which went away when I moved the actuator back and forth a few times
For the time being, this is what is working for me: when the car heats up, turn the temperature to the lowest. When the fan goes up to the highest, increase the temp to fairly higher than normal (like 24 C or 75 F). That usually gets the heat started, and then you get lower it down afterwards.
That seems to be working for me for the last couple of weeks. I will look into it further when it gets warmer. One solution may be to pop the actuator lever out and move the actuator arm completely to the passenger side manually (may not be ideal with summer approaching, though).