Replaced cracked screen with iFixit kit and now touch screen not worki

Thanks BurnieG. I did just that and reconnected all the ribbon cables and they look fine. Same symptons. Phone boots, screen looks good but can't get it off lockscreen cause no response to finger swipes.

I have had this issue before but mine was always due to a tear in the digitizers ribbon cable. There is usually a small rip in the longer of the 2 cables at the base of the connector. There is a part where the cable widens out, and when you feed the digitizer cable from the front to the back of the phone it can tear easily. Sometimes the tear can be so fine it is hard to see. I have also had some tear in places hidden under adhesive tape(Samsung phone). Took me awhile to find that one. The screens ribbon cable has metal inside it. If this metal is folded, it can cause a crack in the metal, and your touch function will not work.

If you still can't find any damage and reseating the cable does not work then you may have been sold a faulty part.

Have you tried doing a soft reset or hard reset on the device? Sometimes this can fix this issue. If you do the hard reset make sure to have your data backed up before the reset. Otherwise it will be erased when the phone is restored to factory settings.

Thanks again BurnieG. I was aware of this issue and I originally tried to put on an iPhone 4 (not S) screen but it did have a rip in the cable. I'm going to take the part back out and closely look at it. It was one of the used screens from iFixit so it is possible it is defective. For now I'll have to put the broken one back one which I've done twice now:-( and order the new one. Thanks for your help!