You have a shop manual? IF not, download one fer free right here:
The thread:
http://www.forabodiesonly.com/mopar/showthread.php?t=132309&highlight=manual,+download
There are a number of good downloads there. Some of the posted links at the early top of the thread are broken, but fixed later "down."
Linkeedoo to the 72
http://www.abodyjoe.com/pictures/Mis...Serv%20Man.pdf
MAP LIGHT, page 8-148. Brown wire at the map light connector should be constant hot. This goes down and wyes off and goes to cig. lighter connector to pick up power.
The map light is either grounded when you open the left door, or when you turn the map switch on. It must be grounded
KEY LIGHT as well as seat belt lamps are supplied by the time delay relay, so IT could be bad
GLOVE BOX LIGHT also gets power from the same pink supplying the map light, so if that part of the harness is dead, fuse blown, not hooked up, none of it will work