I purchased a used boat back last fall and am now experience sounder issues. Garmin 2006C has the # 20 sounder module installed and neither 2006 nor module gives me errors. However, as you can examine attached screens, I cannot gat an accurate bottom to be displayed. Photos were taken while boat was on trailer. However, they are the same regardless at what depth of water boat is in. I have manually adjusted range or allowed 2006c to use defaults (mostly auto). 2006 C manual doesn't provide any trouble shooting advice. GPS charting is great but sounder part appears to be defective. I sense that I am doing something incorrectly and it is not sounder's fault, but I just don't know what it is. Module was/is plugged in and when we disconnected cables to exercise connections (thinking that it was bad connection), error indicators appeared on 2006's screen. We plugged back in and re-booted 2006C and errors went away. But, we are still getting the same screens. Help! Oooops... Iboats wouldn't allow me to upload screen shots. 2006 C screen basically had multicolored red/orange solid line on top of screen going from right to left and will not allow me to adjust range.