Stock head unit connections

I have a 2015 non-nav head unit. I took it out to install a recurve ezq. Now putting it back in the dash, there is one jack on the back of the stereo that I can not find a harness to click in to. Is there an unused connection on the back of this head unit or have I lost a wire somewhere behind the dash?

Thanks

 

Can you take a pic of the empty jack? Might be XM or GPS related.

 

I can tonight but I am at work right now. It was in the middle of the top row of connections.

 

This might help:

 

Excellent reply Tom!

 

This is the back of my head unit. I can not find wires for the second to left spot on the top row.

Thanks,

Peter

 

My 2014 non-nav unit had some empty slots when I took it out for a stereo upgrade.

 

Yeah,
I hooked it all back up last night and everything seems to work. I wonder if it is a spot for satellite radio.

Thanks to all for the input.

Peter