I posted this on the software forum and didn't get any answers but I believe that it is actually a firmware issue so i will try here
Here's the problem. I can jog all three of the axis and they move both directions correctly but, when I hit one of the home buttons, the axis just jerks back and forth where it is sitting. Also, blocking the endstops doesn't seem to have any effect. I can still jog the axis in both directions. This happens with all three axis.
I believe that everything is wired up correctly. The endstops have their LED's glowing and they stop glowing if I block the opto sensor. I do not have the pullup resistors enabled in the configuration file.
Configuration:
[*] Classic Mendel Hardware
[*] Sanguinololu Electronics
[*] Techzone Opto-endstops
[*] Pronterface host software (the latest one, circular control interface)
[*] Slic3r slicing software, integrated with Pronterface.
[*] Sprinter firmware
I tried using an older version of Pronterface just to see if it was a version issue but exactly the same thing happened so I think it is in the firmware..
