What Part is Damaged When Car Defogging Fails?
2 Answers
Car defogging failure is generally caused by switch damage, poor grounding, relay failure, or broken resistance wire, and requires timely inspection and repair at a maintenance shop. Car defogging devices are divided into front and rear window defogging devices. Front Window Defrosting Device: Most car front window defrosting devices use the method of blowing warm air from the heating system onto the glass to achieve defrosting. It consists of a blower, intake and outlet heating ducts, defroster nozzles, etc. The defroster nozzles are installed at the lower part of the windshield, and the length of the nozzles should cover about two-thirds of half the windshield. Rear Window Defrosting Device: The method of blowing warm air onto the windshield for defrosting takes a long time and cannot quickly melt ice and snow on the entire windshield. Many cars use a thermoelectric defrosting device. The thermoelectric defrosting device integrates resistance wires directly into the glass layer, which are visible as several red lines to the naked eye. It uses the car's own current to heat the resistance wires to achieve defrosting.
I remember one time while driving, the windshield fogged up badly, and the defroster button didn't respond, which was really frustrating. Don't panic just yet—it might be due to poor contact or a malfunction in the defroster button. First, check the button switch in your car yourself. Then, pop open the hood or the fuse box; a blown fuse is a common issue—locate the defroster fuse and replace it to see if that helps. If the fan isn’t working, it could also prevent airflow, so inspect the blower for jamming or damage. If all these seem fine, there might be a blockage in the ducts—like my car once had small leaves clogging the vents. Regular DIY checks can save you repair costs for such minor issues. If none of this works, it’s best to visit a professional shop for a thorough inspection.
