My 2002 chevy avalanche is in 4 wheel drive low and will not go back to 2wd.

What is your question?

It has been difficult to switch between 4 low 4 high or 2 wheel drive for about a year. It would do it but it took many attempts before it finally clicked. Now its in 4 lo and when you hit the button you hear clicking then it just stops and stays in 4 low. I don't have any codes or problems showing.