Jeep wont start or turn off

1988 jeep cherokee 4.0 stick 4x4 it wont start with the key or turn off with the key, so far i've replaced the ignition switch, starter relay, and the other four relays on the passenger fender well. i can jump it from the starter when the ignition is on and it will crank up, and i can turn it off by the 2nd to last of the four relays on the fender well. i can also crank it at the starter relay , but not by the key . my mechanic can't figure out what the problem is and he speacializes in jeep, can ANYONE HELP ME?!