Why does the fan not rotate at the first speed but starts rotating at the third speed?
2 Answers
When the fan does not rotate at the first speed but starts rotating at the third speed, it is due to a decrease in the capacitance of the fan's starting capacitor. Replacing it with a capacitor of the same capacity can solve the issue. Below is an introduction to related content: 1. Classification: Fan capacitors are generally divided into two types: starting capacitors and running capacitors, which function based on their roles during operation. 2. Starting capacitor: The starting capacitor assists the motor during startup and becomes inactive once the motor is running; the running capacitor continues to assist the motor even after startup, meaning it remains active. The capacitor in an electric fan is usually a starting capacitor.
Recently, my own car also encountered the strange issue where the fan's first speed stopped working and only the third speed functioned. It’s probably due to the aging of the fan resistor. That component is located behind the blower and specifically controls the speed of different fan settings. If the resistance wire for the first or second speed burns out or has poor contact, those speeds will fail, causing the fan to jump directly to higher speeds. Loose wiring connections could also be the culprit, especially in older cars where plugs are prone to oxidation and corrosion. Unstable voltage in the air conditioning system can also cause erratic fan speed changes and, over time, shorten the motor's lifespan. I recommend first checking the fuse box on the dashboard to see if the fuse corresponding to the fan has blown—replacing it costs just a few dozen yuan. If that doesn’t solve the issue, it’s best to visit a repair shop and use a multimeter to test the resistor value, avoiding the discomfort of a malfunctioning AC during summer traffic jams.
