The same thing happened with my friends N4. The glass, digitizer and LCD all had to be replaced as they all come as one unit. Cannot get them separately.
Sure they do. FYI, the "glass"
is[ the digitizer. If "everything works", then technically all that needs replacing is the digitizer.
However, digitizer replacement is far from an easy thing to do. Not only does it require some specialist equipment (suction cups, heat gun, glue), you're probably going to screw it up unless you've done it before.
Recently got a GS5 and my mom doesn't have a phone right now so I'm handing my N4 down to her. The front glass is cracked and I wanted to get that fixed before I do. The digitizer and lcd are not broken, just the glass, everything else looks and functions fine. I guess what my question is, if I take it to a repair shop can they just replace the front glass or am I looking at around 100ish to replace it all? I'll be going in and getting quoted but just wanted to see if I got any input from here first, it will likely be a week or so before I take it anywhere due to this damn weather.
You can buy just the screen assembly off eBay for about $45, which has the digitizer already mated with the LCD. However, this requires removal from the bezel (again, a heat gun is recommended), then gluing the new one back in. For $60 you can get the entire front assembly (hey, brand new phone!), which is the easiest way to go about things. I'd also recommend buying a new battery ($20) and replacing the old, tired one while you've got the phone apart.
It's not all that difficult to do it yourself. You'll need a T5 TORX driver, something thin, sturdy and plastic to pry the phone halves apart (you can buy screen assemblies that come with all these tools), and some patience. Do everything on a fluffy white towel so the little screws don't get lost. The tricky part is the little rubber gasket thingy that goes over the proximity/light sensor module. Most people who have done a screen replacement have found that reassembly screws up the prox sensor, causing it to always read "near" (meaning during a call the screen will stay off and you can't hang up or use the dialer). The common fix is to put the gasket in
backwards.
There are a number of threads here, some youtube videos, and a good teardown tutorial on ifixit.com.