Dec 31, 2020 | Auto Repair Diagnosis
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A vehicle’s defrosting system is an absolute necessity for safe driving during the cold winter months. Driving with a frosted windshield or fogged rear window and no way to clear it off can lead to limited visibility and dangerous driving conditions.
There are several things that can go wrong with the defrosting system ranging from blocked vents to a defective heater core.
Common reasons for this to happen:
- Buttons Stuck: In some cases a button or knob for the heating controls becomes stuck. Moving them back and forth until it moves into the defroster position may solve this problem.
- Blocked fresh air intake: The fresh air intake is at the base of the windshield. It draws in fresh air, which helps the defroster function. If leaves or other debris are blocking the air intake it will affect the defroster.
- Vent Issues: If the vents on the dashboard are clogged, this will prevent the air from reaching the windshield. A quick vacuuming of the vents may fix the issue, if not the clog may be deeper in the system and require a professional.
- Low Anti-Freeze: The heater core depends on hot antifreeze moving through it to heat the inside of the car. If the vehicle is low on antifreeze, it can affect the heating and defrosting systems. Anti-freeze should be checked and replaced on a regular schedule.
- Malfunctioning Thermostat: The thermostat in a car works like a shut-off valve between the radiator and the engine. It remains closed when the car is first started to build up heat. Once the engine is warm the thermostat opens up to circulate anti-freeze to prevent the engine from overheating. If the thermostat is stuck open, the engine doesn’t warm up, so the defroster will not have the warm air it needs to function properly.
- Bad Heater Core: The heater core is basically a mini radiator that is located behind your dashboard. It is the heart of the heating system and essential to the defrosting system. There are a number of things that can cause a heating core to go bad, it can become clogged up due to contaminants in the anti-freeze, hoses can come loose or broken and control valves can become stuck. A bad heater core will result in no heat, which means a non-functioning defroster.
- Bad Blower: The heating and defrosting system rely on an electric blower motor to move the hot air into the cabin of the car and through the defroster vents. If the blower motor is malfunctioning, the defroster will not work. Issues can range from a blown fuse to a bad blower speed controller. The blower motor itself can also go bad and need replacement.
Figuring out which one of these is the culprit as to why your defroster isn’t working can be a tricky business on your own, if you’d prefer to leave it in the hands of professionals, give us a call today!
