The fact that you don't have codes and both fans are on high, I suspect the AC pressure is high causing the PCM to think it needs to have them on to try and lower the pressure so it cools better. I have seen a lot of DIY people use the Innova 5210 but clearly there are a lot of options. Most of them are around $100 and google displays the most popular when you search for scan tools. However, if you are going to use it then I have found that most of the more basic tools that just read codes and live data are pretty good. I would hate for you to buy a scan tool just for this.
