I have done many screen replacements, but now I did the 5c for the first time. Touch was not working well after assembly so I reseated the connectors and it was even worse... no touch at all!
I reseated the connectors 4 times in total with no result. I wanted to give up but took one last attempt.
I blew on the connectors to make sure there was no debry on them and then took a cotton swap drenched in 100% alcohol and cleaned the connectors very carefully. After assembly everything worked flawless.