Was gonna help a buddy put a head unit in. They said they tried previously and couldn't get it to work. (They were working on wiring in the car while battery was connected...)
So I get there and wiring is all separated so I connected it all, plugged in, and it wouldn't turn on. How likely or how easily can you blow a fuse or fuck something up while messing with the wiring while battery is connected?

if they sit there and let the wires short then they could of easily melted wiring or blown a fuse.

easiest way to see if they messed up the head unit or the wiring is to get some spare wire and wire it up directly onto the battery under the hood+ a ground spot and see if it powers up.

I forgot what its called its better then dubs..