Here is what I found for the 2004 RAM 1500:
Auto Unlock Feature Programming
This feature is enabled when your vehicle is shipped
from the assembly plant and can be disabled by using the
Customer Programming sequence to disable or enable:
1. Enter your vehicle and close all doors.
2. Fasten your seat belt (fastening the seat belt will cancel
any chiming that may be confusing during this programming
3. Insert the key into the ignition.
4. Within 4 seconds, cycle the key from the OFF position
to the ON position four times ending in the ON position
(do not start the engine).
5. Within 30 seconds, press the driver’s door lock switch
in the UNLOCK direction.
6. A single chime will sound to indicate the feature has
7. To reactivate the feature, repeat the above steps.
8. If a chime is not heard, program mode was canceled
before the feature could be changed. If necessary repeat
Hope this helps. If you don't have the owners manual for your truck you can download it from here: http://www.dodge.com/webselfservice/dodge/index.jsp