I think you are about there.
From ELKRP enroll input expander 13. Define the zone definition: burg perimeter, etc. Define normally open or normally closed, or EOL. If it is showing short, do you have a closed door switch connected to it. With nothing connected to the zone input on the keypad, it should show open. You can go to ELKRP status screen and see what the M1 is seeing.
A damaged cap. on the board is not a good sign however.