Bad smell coming from air vents on car when fresh in take is on
I have a 2015 Kia Sorento. I noticed a bad smell coming from my air vents about a week ago when I was in park with the heater on. It's not a sweet smell like antifreeze and it's not a stinky smell like rotten eggs. It's more of an electrical smell. I took it to the dealership and they changed the cabin filter and said they looked it over and couldn't find anything. They said they looked at the exhaust system and for any oil leaks. Found nothing. So I hoped the cabin filter solved the problem. It did not. So only clues I have is car has to be on fresh air intake and the temp has to be halfway before this happens. And it can be smelled from the inside of the car, the outside and under the hood. Anyone have any idea what it could be? Thanks.