True of the locking pin but that shouldn't stop the key switch from going into the accessory position. sounds more like the lower switch is messed up. I had the same problem with the one in my yard plow truck and it was the lower ignition switch itself. it was misaligned on the lower column and wasn't allowing it to go back far enough to go to the accessory position. Yours could be a bend rod as well, the dam things can get jammed inside the column as well. disconnect the rod from the lower electrical switch and try to put the key into accessory position without anything attached on the lower end. if it goes into acc. your problem is somewhere else. That should also allow the pin to move into position to lock the wheel if its not the pin spring.
Technology is great when it works,
and one big pain in the ass when it doesn't
Detroit iron rules all the rest are just toys.