I haven't seen anyone else posting anything similar to this in my searches, so I thought I'd put this out there.
I have a 2017 Model S 75D, I think hardware version 2.5. It's been a mostly great car thus far. But I had a scary issue yesterday and today and thought it would be worthwhile to post here in case anyone else had seen or heard something similar.
Last night, while on a short 15 minute drive home, twice in about 5 minutes I smelled an overwhelming acrid odor, that smelled like burning plastic. I did not see or detect any smoke anywhere inside the car (or outside after parking). The first time, it went away after a minute or two, and I assumed it was coming from outside the vehicle, but then it came back just a few minutes later, while I was parking the car (far away from my house, as it turned out, because I was nervous of a battery fire). Right as I put the car in park, I heard a very loud BANG that I think came from behind the dash. It startled me tremendously. I came out a few times later in the evening (during the Super Bowl) to check on the car and I could no longer detect a smell and there was no visible damage anywhere.
This morning, however, a few minutes into my drive to work, I realized the car seemed not to be heating up (it's winter here on the East Coast, although just now it's closer to 60 out there. But this morning it was in the 30s or 40s). After fiddling with the controls for a bit, I confirmed it - the car is no longer blowing hot air. I can turn the temperature up to 80 and set the fans to whichever vents I choose, but they only blow cold, ambient air.
There was no smell this morning, but it sure seems like something electrical went seriously wrong last night, like maybe a capacitor in the heating system overloaded and exploded or something?
Frustratingly, I'm a week and a half from my service appointment. It's warm today, but it means 10 days or so of coat and gloves in the car. First world problems, I know....