I've had my 01 GP for about 5 years now and the interior lights have never worked. Not a single one. They are controlled by a 10A fuse. If I replace the fuse, it pops right away, so clearly there is a short somewhere.
I've had the headliner down once, but was never able to find the short. Presumably there's a worn wire touching the metal roof which is causing the short. Are there any common areas that may be the source of this short? Any other diagnostic ideas to identify where the short is coming from?
