I enjoy using Netrunner Linux, but Netrunner 15 has an issue.
When I plug my headphones in I can’t hear any sound coming out of them. The speakers work, but the headphones don’t. Is there any way I can diagnose and fix the problem?
Your question is to vague, we’ll need more information.
Are these USB or analog headphones?
What are you plugging them into if they are analog?
Etc.
Let’s see…
They are analog headphones. I don’t know what the port I’m plugging them into is called, but it is a small circular port on the side of the laptop. Headphone make: Sennheiser HD 203.
OK, then this maybe a port switching and muting issue with your Pulse Audio configuration.
To make sure go into audio setup and on the second tab select headphones for output like this:
[attachment=622]
You should now get audio out the headphones, if not then your having another issue.
I’ll give it a try, thank you. 
And it works! Thank you.
If you want pulse audio to automatically make this change from speakers to headphones every time you plug and unplug your headphones, then edit this file: /etc/pulse/default.pa and remove the # from the load-module module-switch-on-port-available line, now save the file and you should be good.