It took my mere presence to fix the issue--like taking your car to a mechanic, the thing worked fine for me--so I created a desktop shortcut for him and spent a grand total of perhaps five minutes working on his machine. The rest of the time I was there we just chatted about various things. He's a retired lawyer who is now teaching Illinois CCW classes, and an all-around good guy, so we talked about this and that and the other thing before I took my leave of him.
I had the balance of the holiday errands to run, so I ran them. My first stop was the grocery store, and when I was coming out, holy shit had it gotten cold outside! (I just looked at the graph now, and I see that while I was chatting with my friend, the outside temperature fell by nearly ten degrees. Shit.)
Next, getting pie! And on the way back from picking up the pie I had to wait for a train...and then I had to wait longer because the gates jammed in the down position. Well, a week of melting and rain and drizzle, followed by a very hard freeze--I suppose it's surprising more of the things don't jam.
After that, picking up a few stocking stuffers, and dinner, and I was finally able to come home.
...and throughout the entire adventure, I was toasty warm. With the outside air temperature near 5° and a wind chill of -6° and a dewpoint of -31°, the interior of the Jeep was nice and comfortable, even with the blower on low. I could have heated the interior to the point of being too warm even in shirtsleeves.
I'm-a call that one "fixed", I think.