Last Christmas my 2011 Chevrolet Volt started to smell burnt rubber when I use the heater. The heating actually still works, despite the smell. Next day I took the car for a couple miles ride where I put the heating to the maximum and see if the smell came back again and again it was warming normally, but if the burnt smell. When I parked I popped the hood and I saw a little bit of smoke with the same smell coming from the engine near the fire wall (where the coolant heater is located). I haven't used the climate control since and the car has worked without any trouble. I just use the heated seats to warm myself when driving it. I saw other threads where the owners reported that the heating stopped working at all, however this does not appear to be the case since the heating still works, just that it smells burnt and may be smoking a bit.