It's a plain hatchback Civic, a 1997 EK. I should probably mention too that it's right-hand drive, it being a UK car (so the steering wheel and interior fuse box is on the right hand side of the car - might affect where the dome light wiring is routed?).

I imagine too that it is difficult to get to the dome light wiring if it is not routed to the interior fusebox; the layer of felt fabric that lines the ceiling looks like a challege to peel back!

 

this is what I found for you "It's green with something usually green/red, switch side, white/blue fused power supply, i would firstly check under hood fusebox, look for "backup" fuse or dome." Also check the wires running up your A pillar the same way (probe) that wire will be there.

 

also do only what you are comfortable with, if you think you will damage the headliner DO NOT try to do it. I feel the best place to locate it would be the A pillar solder on your positive lead and ground your hardware, should be fine.