Well... Figured it out with a flashlight, a mirror and an awl! The first picture is what you'll see when you pull the gauge panel. Albeit, the plug-in portion will be down inside the receptacle.
The second picture is of the top of the connector, which you can't really see without a mirror. Notice the gray pivot piece is held by that little back rectangle and tinier hollow square. You need to push that in, to release the gray pivot piece. That's where I used the awl.
The last picture shows how the gray pivot piece slides to the left after release. It will go all the way down 90° so the plug will release from the receptacle completely!
