Why is my phone still in headset mode even though it's replaced?

Dear iFixit and others,

A while ago my Samsung Galaxy S4 got wet resulting in the fact that I could not charge my phone anymore (it still worked) and that it didn't produce any sound anymore.

Since then I've opened my phone with my repair kit, carefully cleaned the inside and have replaced the USB port, Audio Speakers and Audio Jack socket. Now the USB charging problem is fixed, but the audio remains a problem even with the new replacement parts.

Unfortunately I keep having the "there is a headset connected to your phone" sign, resulting in that the phone won't produce any sound without head plugs.

Alternatively, when a headset is inserted the phone does produce sound through the earplugs. Thus, I can't use the phone anymore without earplugs with me at all times nor can I use the speaker function anymore.

My question:

Why is my phone still in headset mode, even though I replaced the audio jack socket and the speakers with completely new parts?

I don't know what else to replace to solve this issue. And normal audio is a pretty important function to miss.

Looking forward to hear your suggestions on what to try next.