The tongue light is on a separate circuit from the door and the outside "scare" lights. It has its own switch and usually can only be operated from the outside.
The other two are operated from the inside - usually from a wall-mounted switch. If none of these two come on, check:
1) the fuse panel 2) for loose connections in the wall-mounted switch 3) the light bulb(s) in the exterior door and scare lights. I'd check the fuse panel first, then the bulbs and finally the connections in the wall-mounted switch.
The manual is generic and will not provide you with information about this problem. If you want to obtain a manual to access general information about the RV , go to the Keystone website (
www.keystonerv.com), click on Customer Service, then click on Manuals. Find the year (2003) and go from there----download it if you want. Note that the manual is not model specific.
And welcome to the forum, BTW!