Q: Use Internal Speakers While Headphones Plugged In

I have a solution involving kext modification which is not allowed to be discussed on Apple forum. Just do a quick search on Google you can find my post on Ask Different.

I am curious about your post on the other webpage, could you wrote the link to that treat please?

I have this problem too.

I'm using an iMac and would like to leave the headphones
plugged in all the time (headphone jack is on the back) and would like the
ability to switch the audio output between headphones and the internal speakers
without having to unplug (and plug back in) the headphone jack all the time.

Will this issue be fixed with macOS Sierra?

It won't be fixed, because Apple does not consider the behaviour as working correctly as designed. In other words, the behaviour is not a bug, it's a feature.

I already got a warning so I will get banned.

Ok, but a change in behaviour would be much appreciated

Send Apple feedback. They won't answer, but at least will know there is a problem or a suggestion for improvement. If enough people send feedback, it may get the problem/suggested change solved sooner.

Feedback

Thanks for the suggestion.

I've just sent them an "Enhancement Request" for this issue

You are welcome.

Yeah! Just keep this conversation / feature request alive!

But anyway, if they would fix that bug/feature issue they will probably include that fix in next OS X... that means, they really do not care about old version of the MAC OS...

Or any version at all according to that logic, and if (as I very much doubt) they are planning on changing it we won't know, and if we do we can't tell anyone.