My fiance's old car had this problem and it was just a faulty dimmer switch. I just bypassed the switch and the lights worked again. That is a possibility.
EDIT: Unless with these cars all the other lights that are working are also controlled under the dimmer switch...I am not near my car to test this out, but I am sure someone else who is wiser will chime in
[This message has been edited by MacGyversMullet (edited 02-18-2014).]