Disc-Aux button not working

[bepop&rocksteady]

So a few days ago the disc-aux button stopped working. It will go to the disc function but it will not go to the aux function. Has this happened to any one else? Any ideas on how it can be fixed without sending it in to be fixed by a professional?
Thanks for your suggestions.

[pancit175]

Obvious question but do you have something plugged into the aux port?

There may be something wrong with the plug itself. The aux plug also has a connection that detects if a aux cable is plugged into the socket in order to enable the aux source.