Just about up...... Don't want to be though!!
The Sorento is quite a nice car for a Korean make (I used to work for Daewoo ). I think they are taking a lot of their styling ideas from Mercedes, and probably using Merc engines under licence too. I know Ssangyong were.
Anyway, to get back on topic. I was thinking about this last night (yeah, sad I know).
The problem occurred when you plugged the switch connector for the N20 in and it sparked. After that things started to go dead. There's no fuses blown but something is making the battery go dead (unless its the battery itself?).
I'm thinking that the N20 solenoid may be on, which draws ? amps... maybe 10A? This, if its being energised permenantly, will flatten the battery nicely and, depending where it is connected to, may cause sufficient voltage drop across the feed wire from the fuse box to stop certian critical systems from powering up??
Just a guess.
Steve