Just throwing this out to see if anyone else is having this issue.
I have a 2017 Cruze RS.
When its cold, usually below 20 degrees Fahrenheit, I will get it to operating temp. Its blowing good heat from the vents, gets nice and warm inside. However if I have to stop for lights or maybe sitting in a parking lot, the heat will go cold. Then as soon as you start moving again the heat comes back, like its magic.....but its not, not really. Anyway, I have taken it many times to the dealerships last year and again this year where as they tell me there is nothing wrong and cannot fix it, or one recognized the issue but refused to write it up as an issue, then told me to make a trouble ticket with Chevrolet. That was a joke......nothing more than a satisfaction survey is what it turned out to be, which I told them I was completely unsatisfied.
One of the dealerships told me that it was the heater core and was designed to small and that I should turn the blower motor down......are you kidding me? I shouldnt have to to do that. However I even tried that and that doesnt work.
I told them my opinion and that there wasnt sufficient flow through the heater core to keep the heat up at idle.
Tried attaching the video, I put on youtube, but it might be to big of an attachment. Its under "Cold weather issues with 2017 Chevrolet Cruze".