Jim Grant's Tech Tips
01 Ford Focus, Ventilation Woes
Q: We have an ‘01 Ford Focus wagon that has two problems with the heating system. First, when we run the heat defroster unit, it blows dirt and dark black particles from the top blowers. Secondly, when you turn the blower dial on, the AC green light comes on to activate the AC and not heat/defrost on blower levels 1-4. We turn that off to get heat. The air filter under the dash was changed and we were told it was “road dirt” that is blown all over the dash from this. Needless to say, it is annoying and dirty. What would be the cause?
- D&L Doyle
The air filter you’re referring to is often called a pollen or cabin air filter. If you’re getting road dirt in the vehicle then the pollen filter or cabin air filter is not installed correctly or the housing or housing gasket for the filter is damaged. The only way for the outside air to enter your vehicle is through this filter. If dirt is entering is has to be getting by the filter. A closer inspection of that area of the vehicle has to be performed. ALLDATA Information Systems does show 2 Ford Technical Service Bulletins (TSB) # 03-18-2 & 01-9-2 addressing sealing and water entry problems on ’00 to ’03 Ford Focus. As for the A/C turning on and affecting the heat of the vehicle when the blower is turned on is a strange problem. The blower switch does send a signal to the heater control module but the module doesn’t control the blower speeds or the temperature control/blend door. Other than the signal from the blower switch the electrical circuits of the 2 components are separate. It will take some investigation on the vehicle to determine just what is going a-muck there.