One of the problems, Tom, is that the OBD specification doesn't require a specific set of codes for certain sub-systems and many manufacturers are different. I have new code reader software for my Palm that is better that what I wrote. We can try it on your truck if you like. Are you free for lunch today?
Many multi-vehicle scanners fall short in this ares. Also, most programmers are vehicle specific, which may or may not help them in reading these extra codes.
I may work on making my software I was writing read other addresses -- but I'm not absolutely sure it will work.
In the meantime, if you're free, I'll head down there at lunch time.