I'm just not sure. Most wper harnesses are pulled into the bulkhead connecter just like a engne harness of forward light harness. Keeper on the top and the bottom of those connecters. bootm one can be a pain to get to.
Some will pull the wiper motor away from the firewall and fish the linkage apart at some junction, through that opening. I prefer to remove the radio and work through that opening to remove the pitman arm from the motor.
Hope this helps