I was having a smell and hot air coming from the ac unit. Went and had it serviced to fix the problem. 386 dollars later and to my dismay thrash was getting into the ac unit. vents and ducts. I bought this 2002 ford focus as a late model used car. One option listed was a cabin air filter. I went to several auto parts stores to find one and the filters were all too big, I even went to the ford dealer to get one and all they could get was the tray that one would fit in but no filter. Come to find out they never made the filter, thus all the time I was sucking in dirt and leaves every time i ran the ac or defrost cycle. Call Ford and told them of the situation and they did not know what they should do. I suggested that they make the part and have a national recall. smirk i heard on their end. problem never resolved. I went to walmart and bought a home ac filter and cut it to fit and had changed many times until I traded the car in.