Dome Light Not Working

Hi I am new to the forums I hope I am posting this in the correct place, I searched for more info but have not been successful. I recently acquired a 91 mustang that has a LOT of wiring issues, so many in fact that I won't even bother trying to fix most of the interior lights. one that I WOULD like to fix is the dome light, I just want it to turn on when a open the car door. I don't even know where to start! right now is the best time for me to fix it because I removed my headliner to re-do it and I have easy access to all wires. when I took it apart I ended up with 2 dome light pieces and 2 broken wires. I see a brown wire which I assume is a ground and a blue/black wire which I assume is power, I don't know where to hook them up to where the light will work or if any of the parts work at all. I need help figuring this out. These are the best pictures I could get right now. I don't know if they are helpful but it got dark on me. if you need more pics just let me know and I will post them tomorrow.

@RaggedGT thank you for the nice welcome. I will be posting more pictures soon. It sounds like my first step is to check the fuse, then then dimmer switch and hopefully it wont be anything too difficult to fix. I don't have a multi meter so I will go to the store tomorrow to get one so I can check the blue and black wire for power. I think that this dome light does not belong to this model but I've heard of people making it work. I am going to the salvage yard tomorrow to see if I can find the original dome light along with some other odds and ends I need for this car and see if that helps.

Time for an update: I got it all working! I am so happy to see that light come on every time I open the door.

I started by testing the fuse which checked out. I then tested the dimmer switch which was faulty I changed it for one I had gotten earlier at a junk yard. still nothing. I ended up tapping fuse #4 on the diagram and running a new wire, I grounded it and it worked, I had to replace one of the bulbs and then the door switch assembly and now I have a dome light that works.
This was all started with installing a new headliner (which was a much harder task than anticipated since the backboard disintegrated and spilled a ton of black foam dust on everything! I had to drive 150 miles to the next town over to get a new backboard. all in all it was a good project and the results are fantastic, sorry for the poor quality of the pics.

karthief said:

Congratulations, they can be a fight. Did I see a sun roof option there? I got one with a pcv back, long ago don't remember where, I also swapped the dome light in the roof for one in the rearview mirror, extra convertible parts.

Click to expand...

Yes there's a sun roof latch. This whole thing started because I wanted to reupholster the roof of the car, the backboard literally turned into dust. I decided to delete the sunroof since it was sealed with caulk and the latches are broken. luckily I found a excellent condition backboard for my exact model except without the sunroof for only $50 and I decided it was meant to be.