I have an original brown box display that I added a mobile processor and Field Doc to last year to map.  It worked great.  Put it back in the combine (9600 w/side mount moisture sensor) and had error messages.  Reprogrammed the mobile processor to Harvest Doc cause I couldn't remember if it was Harvest or Field.  Now I can't get into the Key Card option to change it back.  The option is there,  just can't select it.  Any ideas how to get around this?