So, not to long ago the interior lights including trunk, glove box, dome, and map lights went out all at the same time. I checked both fuse boxes and everything seemed fine. made sure all the bulbs were working which they were. Even went back and checked the fuses with a dummy light. Not sure where to start next or where to look, any advice would be great before i start taking things apart.

It's gotta be a power issue because there are separate grounds for several of those circuits.

According to the FSM all of those get power from Fuse # 2 in the main fuse box under the hood.

Ok, i'll check the fuses under the hood again. What else could it be:-\

Ok so i checked fuse no 2 under the hood and its fine. What else could it be.

Are the gauge/climate control lights working or not?

Yes both are working.

You verified there is 12V on both sides of the fuse?

Probably a harness issue.

Next step is to find out where the circuit is broken. Could be in one of the junction blocks at the firewall. Could be at the fuse panel inside the car, could be another junction between the fuse panel and lights.

Check here to download a copy of the FSM for 2000+ Legacy. http://www.main.experiencetherave.com/subaru_manual_scans/

Check out the wiring diagram section to find out where the wiring for the lights goes in the car.

 

I suppose it can't hurt to check the grounds for some of these lights.

A somewhat similar thing happened to my 95 when I took off the roof racks. The roof of the car was no longer grounding the lights correctly. Solution was to make sure all screws were tightened correctly and make contact with the roof. To check for this try pushing the plastic panel that makes contact with the roof and see if the lights flicker on.

 

If that's not your problem, you could check out a wiring diagram and find out where your dome light wire is and trace it back to the lights checking for anomalies.

Ok, ill check a wiring schematic and see if i can find anything as there wasn't anything out of the ordinary on the roof.