Have you pressed it forward multiple times? It should be like this:
Forward one time to go low-beams --> forward once again to go to high-beams --> forward once again to go to AUTO --> forward once again to go to low-beams... and forever on and on cycling between those three options. I thought it defaulted to AUTO each time.
Wait, that's a FORSCAN thing, too, where it won't default to auto upon starting of the truck, but that's the actual selector switch. Could you have modified that setting as well?