Reasons for Poor Performance of Car Windshield Defrosters
2 Answers
Specific reasons for the poor performance of car windshield defrosters are as follows: 1. The reasons for poor performance of car windshield defrosters include broken resistance wires, poor grounding of resistance wires, and switch damage. Other causes may include relay failures, etc., which require timely repair. When the resistance wire break is short, it can be repaired using conductive material based on epoxy resin, then covered with adhesive tape. If the break is too long to repair easily, the rear window glass should be replaced. 2. Introduction to the front window defroster: The car front window defroster uses warm air from the heating system blown onto the glass to defrost. The front window defroster consists of a blower, warm air inlet and outlet ducts, and defroster nozzles. 3. Introduction to the rear window defroster: Cars use a thermoelectric defroster for the rear window. The thermoelectric defroster integrates resistance wires directly into the glass layer, using the car's own current to heat the resistance wires for defrosting. This method is only applicable to the rear window.
Last time my car's defrost function had issues, and after checking around, I found the heating system was the key. If the heater core is clogged with rust and scale, hot air simply can't reach the windshield, and the air blowing feels cold; if the fan motor is stuck or burnt out, the motor won't turn or makes loud noises with weak airflow, making defrosting sluggish; control switch failures are more common, where the button doesn't respond when pressed, possibly due to oxidized contacts or loose wiring; ducts and vents clogged with dust or leaves, or cracked ducts leaking air, causing all the hot air to escape; don’t forget faults in the AC system—defrost mode requires the compressor to assist with dehumidification. If refrigerant is low or sensors fail, it can’t adjust to the right state. Heavy winter fog blurs vision as soon as you drive, which is too dangerous. It’s best to find a good shop for a thorough check before it turns into a bigger problem.
