The end cap comes off with just this one screw.
With the end cap removed, you can remove the screws holding the vent, and the screw holding the end of the trim piece. The plastic on the end of my trim was broken and long gone, so the screw wasn't doing much.
Also pick this little plastic cover out, and remove the two screws its hiding.
At this point, the vent just pulls out. Be sure to get its little level back into place on reassembly....
You need to pull the connectors off the flasher switch (or pull the switch out of the trim), cigarette lighter, and clock. Note also (1) the rubber tube that runs to the back of the little round grill (to sample cabin temps); and (2) the trim light bulb -- both of which need to get nestled back into place when the trim goes back on.
In addition to the broken mounting tab on the end, the flasher switch retaining tabs snapped off despite trying to avoid exactly that. Cheap West German plastic breaks after a mere 35 years.. Pffff...
Closer still....
