You have to take off a lot of screws, the seal for the cowl, the cover plate under the top cover around the wiper arms.
Then you can try to remove the "clip" holding the motor onto the arms. All this while leaning over the fenders and working near the firewall - lots of fun.
When the motor is out, you can take off two screws and the motor will come off and leave the three brushes and their springs all askew. No adjustment for the Park switch on that side at all. Put that back together and get the brushes to stay in place with thread that will pull loose when the the motor top is back on loosely.
If you take apart the other side and remove about six screws you have access to the gears and a the Park stuff. There is a contact point that works when at the "low" position. Mine was clean and making contact - put it back into the truck enough to plug it back in and tested the motor function. Should have tested the continuity and resistance but did not see anyway to fix anything else as the plug does not allow access.
Still did not park... will get another motor someday and replace it after fixing more important things.