Hi
Happened to me the same problem, what I did was to inspect well near the connectors and set me well that a connector had broken and what I did was I made a bridge with a silver writer. and it worked but I had to connect a new screen for it to work and then place the iphone screen.
And iphone is working properly
Bad Part
http://www.flickr.com/photos/99104195@N08/9309159184/
Fixed with Silver Writer
http://www.flickr.com/photos/99104195@N08/9306373631/in/photostream/
i use a Macro Lens for iphone 5
Link Silver Writer
http://www.amazon.com/CIRCUIT-WRITER-SILVER-REPAIRS-TRACES/dp/B00B88B9KI/ref=sr_1_3?ie=UTF8&qid=1374075517&sr=8-3&keywords=circuit+writer+pen
never use it direct the writer, put some on a sheet with something that has the fine point you can do it without touching other connectors or you can make a short circuit.