No Audio on left Headphone plugged at the front panel

Hello,
I have no sound on the left speaker of my headphone when it is plugged at the front panel.
when plugged rear it works.
when plugged headphones into the desk speakers logitech 2+1 it works.

my desk speakers logitech 2+1 are plugged at the rear panel it works fine.
when I plug the headphones at the front I get sound only from the right speaker of the headphone.
System newly setup with all drivers.
Attached picture of systemspecs.
I have changed front panel audio connector settings from hd audio to AC97 and vice versa.

I would appreciate it very much if anyone have an advice, as I do long gaming sessions after everyone is asleep and I cant hear from desk speakers at night, not to make all neighbours and family upset.

If you connect your desk speakers to the front panel,
is the left channel still silent?
If it is, the audio connector or wire to the motherboard is faulty.

One workaround is to get a 1to2 audio 3,5mm plug that you
connect to the rear panel audio output, headphones in one, desk speakers in the other.
http://i1.ebayimg.com/images/g/n2wAAOSwm8VUviMo/s-l225.jpg
Turn off/down desk speaker volume and use the headphone during silent hours.

Hi if one of both deskspeaker and headphones plugged back work properly.
if one of both plugged at the front panel, only sound from right speaker either deskspeaker or headphone.
checked by using slider in realtek audio menu.

is there a simple way to check audio connector or the wires except that ı dont get a sound on one speaker. maybe with some tool or software. just asking.
in worst case ım gonna purchase 1to2 audio plug

Make sure that the headphone jack is pushed all the way in, sometimes there can be a lot of resistance.

Edit: 3.5 mm headphone plugs/jacks can have 2, 3, 4 or 5 poles (google if you familiar with the differences) so you have to make sure plug and jack are compatible.