Is It Normal for a Car Blower Resistor to Get Hot?
3 Answers
It is normal for a car blower resistor to get hot. The function of the car blower is to blow the cold air from the air conditioning evaporator or the hot air from the heater core into the car. When the blower is turned on, if the lowest temperature is selected, the outside air drawn in through the external circulation will be at the ambient temperature, which might be slightly higher because the air intake for the external circulation is usually located between the windshield and the engine compartment, increasing the temperature of the incoming air. Below are the functions of a car air conditioning system: 1. Temperature Regulation: This is the primary function of car air conditioning. In summer, the cooling system produces cold air to lower the temperature inside the car. In winter, except for large commercial vehicles that use independent combustion heaters, most vehicles utilize waste heat from the engine for heating. 2. Humidity Regulation: Humidity greatly affects passenger comfort. The humidity inside the car should generally be maintained between 30% and 70%. Standard car air conditioning systems do not have the capability to regulate humidity; this can only be achieved through ventilation or by using advanced luxury car systems that integrate heating and cooling. 3. Airflow Regulation: The speed and direction of airflow significantly impact comfort. If air is blown directly, the speed should be limited to a certain range when the temperature is appropriate. The speed can be adjusted based on passengers' living environment, age, health, and personal preferences. 4. Air Purification: The quality of air inside the car is crucial for comfort.
Well, I've encountered many similar situations. It's normal for a car blower resistor to feel slightly warm during operation. After all, it consumes some current to regulate fan speed, converting it into heat - similar to how a light bulb heats up when lit. However, if the resistor gets hot enough to burn your hand or emits a burning plastic smell, that's definitely abnormal. Common causes include a faulty resistor itself, a short circuit in the fan motor causing excessive current, or overload due to aged wires with poor connections. Symptoms typically include unstable fan speed control, such as being stuck on high speed, unresponsive low speed adjustments, or complete failure. I remember once my friend's car had a resistor so hot you could fry an egg on it, resulting in the fan only working at high speed - driving in summer felt like sitting in a sauna. If not addressed promptly, it could burn out the entire blower module or even cause a short circuit fire. So I recommend immediately turning off the blower when noticing abnormal heat, checking fuses and wiring condition; it's best to visit a repair shop for testing and maintenance to prevent small issues from becoming big troubles. Reminding technicians to inspect these components during regular maintenance can save you a lot of future headaches.
It is normal for the blower resistor to generate heat during operation, as the current passing through the resistor naturally produces warmth and should not become excessively hot. However, severe overheating, to the point of being too hot to touch, emitting smoke, or producing a burnt smell, indicates danger. This typically signals a resistor malfunction, short circuit, or fan motor issue, causing excessive current and overheating. If left unaddressed, it may lead to uncontrolled blower speeds (e.g., only operating at high speed), system damage, or even electrical fire risks, particularly affecting cabin safety, especially with frequent air conditioning use. Upon noticing such symptoms, immediately turn off the AC, check if the fuse is blown, and inspect wiring for signs of melting. It is advisable to visit a professional shop to test resistor values or replace components. For prevention, keep the blower's ventilation area clean and avoid blockages like leaves or debris to reduce overheating risks. Regular comprehensive electrical inspections are recommended.
