Hi Scott,
great. Next check if KMotionCNC | Tool Setup | M3 M4 M5 S Actions are configured to use the Correct Jog Programs. Post a screen shot.Yes the jog commands work. I can jog in both directions and at varying speeds.
What happens when you enter M3 S500 in KMotionCNC's MDI? Check for anything printed on the KMotion.exe Console Screen.