Filtration system and smells

I recently bought a car. When you turn on the air (not the ac) from the vents you get a nasty smelling odor. If I put the A/C on the odor is almost not detectable.

Any idea as to what this is? I would think from the odor that the prior owner had cats in the car.

Model and year would be helpful. First thought is the cabin air filter, next thought is the heater core, is it a sweet sickly smell? Third is a clogged vent tube for ac.

2007 santa fe. No sweet smell that for sure. It smells like a cats litter box.

There are many things to try out. There is probably stuff growing in your dirty, wet AC evaporator case. The bacteria and fungi release volatile organic chemicals. First, make sure your cabin air filter is clear if you have one. It may be full of cat hair. Make sure the drain for the condensed water is clear. Make sure you put the AC system at the correct setting when you turn the car off. You want it anywhere but recirculate (max AC) or off.

If you have no cabin air filter, you may want to try and get to the AC evaporator to clean it out. Some are easy to get to. What kind of car is this?

Last week click and clack had a suggestion for blowing out the clogged tube, if your brain can stand it listen to last weeks show.

2007 santa fe. how can i find the cabin air filter and where the problem is? I’m a single mom with two kids and this is a whole new experience for me to work on.

Most likely a clogged drain from the A/C or maybe you might be close about that littler box comment and you might have or had mice in there. Do you park you car where mice might find it?

The drain is easy to fix. You also should check the area in front of the windscreen to make sure it is clean and drains properly under the vents.

The auto store will have spray cans of stuff to spray in the air intake to reduce or eliminate mold type problems. Lysol will also work almost as good.

Good Luck.