Hello….When we run the heater at any speed it smells like it is a burning smell. It is fine with the A/C running. I checked the cabin air filter and it looks fine, but can use a replacement. It is a really bad smell and we are using recirculation and even outside air. Any ideas on what to check? We willend up taking it to the dealer, but want to check here first if anyone has any ideas or tips. Thank you.