What? Resistive heating is almost 100% efficient. I guess maybe you're using "efficiency" in its colloquial sense, and yes, in the right conditions heat pumps can provide a lot more heat per consumed watt than resistive (as I recall this is called the "coefficient of performance" and is often well above 100% for heat pumps). I suspect there are several reasons they aren't widely used in cars, two of which are that they tend to be pretty anemic -- they don't blow hot, they blow warmish, the benefit being that they don't require much energy to do it -- and they are basically good for nothing once ambient temperatures get down toward freezing. So if you're going to be relying on resistive heating in the winter anyway (since there's not much heat in the air for your heat pump to harvest) so you're not going to be improving your worst-case performance, why spend the money/weight/complexity on a heat pump? The more so if it's going to take a long time to warm the car even in shoulder season, so you're probably going to use resistive heat then too, to juice the heating until you get the cabin warmed.
It would be a classic example of why one should always plug the EVSE in when parking at home. Car won't drive if EVSE is plugged in... (Though I haven't tried to see what would happen if I had the wife plug in the Volt while I say behind the wheel in 'D')
In the same way that I haven't assumed that all claims of "autonomous acceleration" for Teslas (or any other make) are legit, but rather much more likely have some other factors (many times human), I'm not going to assume the same for GM here either...
What is interesting is GM is sending someone to look at the OP's car specifically. As if they don't get that kind of telematics from the vehicle already. (I mean really, isn't that what OnStar is for?)
Too whimpyAt least when GM vehicles drive themselves, they only crash INTO walls, not THROUGH them like Teslas.
