First let's start off with I have research all over this website and have found two exact identical problems but with no resolution. I have a 2003 early model 6.0. Current codes are p1832 and p1820. So my current problem is that I can engage my transfer case into both for high and 4lo but it will not engage out of either. I have changed both relays and transfer case module behind the glove compartment. I have tested all relays for power and I have tested for power at all my fuses and everything checks out. With my scanner looking under gem 4x4 I can see that it recognizes neutral and all other gears. I can also see that it recognizes brake pedal position. It also recognizes my dash switch input so I know that it good. I have swapped out the tcsm with another know good one with no change. Im at a complete loss. If anyone can share some insight that would be great.