I have a loaded 97 2500 with the overhead computer that shows the outside temp. There is a button to change it to metric and a button the says temp/comp. When I push that button it just turns it off. I was curious what else its supposed to do other then show the temp? I know there isnt any sensors on the motor but shouldnt the thing do other stuff? I have had the truck for 3 years now and have wondered that ever since.

 

It should read outside temp and compass heading. None of the fancy mpg, etc of the 24 valve though.
This might help you http://dodgeram.org/tech/repair/elect/compass.htm