Blower Filter

I think your looking at your heater core, I dont see a filter http://bit.ly/hOHbE

Do your best to clean all debris out of the heater box so you don't get mold/mildew growing in there. You also don't want the organic matter in there decomposing and possibly corroding your heater core. Some good disinfectant should work well. You don't smell coolant in the heater box do you? Leaves and sticks that fall onto the cowl plenum at the base of your windshield can fall into the heater box and collect there and block the drain. That's why it's good to keep the area at the base of the windshield clean of sticks and leaves