How to fix broken spring contact on Display assembly?

i believe you mean the 2 prongs of the home button? they are the only 2 prongs I can think of on the back of the display. Check and see if your home button works..if it doesn't then you'll need to purchase a new flex which are pretty cheap to buy. unfortunately it'll mean following a guide to remove the digitiser to get to the home button. Once that is done the replacement is straightforward..there is only one hole in the midframe for the flex to pass through. you will just need to use the double sided adhesive tape to stick the flex on to the home button and on to the back of the midframe.