Hole in my wife's jacket.
It goes all the way through.
Yeah, Problem. Burned a hole clean through my wife's jacket and started to singe her sweater before we smelled smoke and realized what happened. I should have known better- this happened right after I replaced the fuse that fed the heaters, which had blown. I assumed it had blown because these were added to the cigarette lighter accessory circuit and we'd accidentally overloaded it- I guess not! There was obviously a defect in the heater. Furthermore, the bottom heating element had previously burned a small hole in the seat fabric about a month ago- see the small (6mm) hole in the seat fabric in the third photo above. Since it was less severe and the only example, I'd chalked it up to a one-time defect and resolved not to buy again. I disconnected that element and continued to use the others. Evidently, there is a big design or manufacturing problem here! Buyer beware: think twice before buying cheap seat heater kits from China, and definitely not from this seller. (EYESAUTO ELECTRONICS)
I'm messaging the AliExpress seller to see how we can resolve this- I doubt I'll be made whole, given the nature of a trans-pacific factory-direct transaction, but I can hope. Buyer beware!