If you meant to unplug the cable and check the pins for current, all pins from 1-13 have 4.56 v to ground on the cable plug.

I am wanting you to short Pin 11 to Gnd so that if Mach is seeing the port you will see the LED for the X++ Limit switch on the diagnostics page change from Off to On or vice versa depending on the active state you have set in ports and pins. If the LED does not change state and you are positive that you are touching the wire to the correct pin then Mach is not seeing your port or the port is not functioning properly.
Hood

The program will not let me reset the switch and it does indicate limit switch triggered. I will try and plug in the cable to reset the red button. When unplugged the cable, the computer sounded as it knew the cable was attached. This lead me to believe the port is functional.

Ok either change the active state of the limit as in my pic or connect the wire like you are going to do.
Hood

The problem I am having is that when I unplug the cable, the limit triggers again and must be reset. I can only reset it with the cable plugged in. When I unplug, the limit triggers.

Ok look at the pic I posted, it has a green tick in the active low for the X++ limit setting, do that and you should be able to reset, if not then check that your E-Stop input further down that page also has the green tick.
Hood

I set to active low and it reset without plugging in and grounding pin 11 made no change to the diagnostic screen, as far as I could tell.

Ok if you are 100% sure its pin 11 you connected the wire to then Mach is not seeing your port or the port is not working.
Hood

I checked a few more times and no change on the screen.

Wait! I touched a few other pins and there was a change on the screen and I tripped a limit by accidentally hitting another pin.