Bob, You will need to relieve the pressure or lock the arm. To relieve the pressure you will need to carefully remove the forward or left side arm bieng sure to hold on to it. as it could inflict serious damage, if you let it go. Then slowly unwind it until there is no more presure, again being careful not to let it unwind by itself. You should also count the turns so you can reinstall it with the same pressure. Carefree also put a hole in the arm that allows you to install a large cotter key that will lock the arm and not let it turn. The problem I have had with that is finding the hole and lining it up. I have found that drilling a small hole through the tube and awning arm with the awning fully extended, and screwing in a screw will lock the arm in place worked the best for me. You will need someone on the roof of the coach and someone at the outer end, to remove the awning and reinstall it. Once you have done it, it's not a hard job. Just be sure not to let the arm unwind by itself, or it can damage the coach, or worst yet YOU. I am assuming your 2004 is like my 2003, and the arm is wound from the left or forward end, but you be sure. I hope this helps.
Jim