OT: Radio dead, in my friends Subaru

Well this is totally off topic but my friend needs help. He installed an Alpine headunit in his Subaru and its totally dead. When he went to swap in the stock one, that one's totally dead also. All fuses are fine, but now the radio wires get no juice and his overhead lights dont work. What could it be? All the wires are connected correctly and i doble checked everyhting, Im stumped. If you have any ideas, please share, we need this resolved! thanks guys.
 
Thats what im starting to think. both head units work, but when we were tinkering with he wires, the car side pos and ground (black and red) wires touched and sparked, so that has to mean something is working. but once its all hooked up it dont work.
 
im not a pro on reading wiring diagrams, and i suck at being psychic. and spelling. but im going to pretend that its a 99 subaru impreza rs. the diagram shows the yelo/blu and the wht/yelo wire going to the interior light system.

the yello/gree wire goes to fuse 9 15 amp fuse labeled B52 in the FUSE AND RELAY BOX... the blu/red goes to fuse 2 15Amp fuse labled F68 in the MAIN FUSE BOX however before getting there it goes through some kind of .. ah ****it if you want me to post the diagram PM me with the year make and model
 
id imagine if you folllow the green wire, and the ylo/blu wire that goes from the radio to the interior lights you will find a common fuse.


save this image to your computer as i wont host it forever.

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Something else I just thought of. If you have speaker wires shorting out on each other or to ground this can cause the radio to shut down.