Headphone jack not working. Replacement, too.

Have an iPhone 5 with a functional charging port but nonfunctional headphone jack. Audio would play through the speakers but not through headphones. Replaced the port/jack assembly, problem persists.

I found a single reference in another post that says the ground strap...

https://www.replacebase.co.uk/media/cata...

...was the culprit, and replacing it would solve the problem. I did move the ground strap from the old flex assembly to the new so that seems to make sense. I'm a little hesitant because I've only found that ONE single reference anywhere. Could there be another problem here, or is "bad ground strap" the actual problem?