I just reread what you have posted...My understanding is this. You are stuck in 4WL. With the truck in neutral and with your foot on the brake,you push the 4WD button on the dash and nothing happens. When you push the button, can you hear anything make a noise? Like the shift motor itself or a click from the 4WD module in the rear of the cab? Yes it could be the switch on the dash, but in my experience, it is rare they go bad.