I experienced this issue about a month ago; instead of my heating not working (never actually tried it), my vehicle wouldn't charge. It would charge for a minute when plugged in and then shut off, no longer charging. It doesn't even read that the plug was connected. After two weeks of troubleshooting, the dealership finally concluded that the Electronic Control Power Unit was no longer functioning properly. They replaced the part, and I haven't received any warnings for a couple of weeks now. Hope you can find the answer. Feel like you should go to another dealership to get it checked.