Why Does One Car Fan Spin While the Other Doesn't?
4 Answers
The reasons why one car fan spins while the other doesn't are: 1. The water temperature has not reached the required level; 2. A relay malfunction; 3. An issue with the temperature control switch. The car radiator is mainly used for engine cooling and coolant heat dissipation, ensuring the engine does not overheat and fail. It consists of fan blades, a car fan belt, and an electric motor. The maintenance methods for a car radiator are: 1. Avoid contact with acidic, alkaline, or corrosive substances; 2. Use soft water to reduce scale formation; 3. Choose a non-corrosive antifreeze; 4. During radiator installation, avoid damaging the cooling fins or denting the radiator to ensure cooling efficiency and sealing.
I encountered the same situation a couple of days ago and just got it clarified at the 4S店. The most likely reasons for the electric fan not working are a faulty relay or a blown fuse—simply put, it's like a power socket tripping. Another common issue is the fan blades getting stuck, which often happens after using a high-pressure water gun to wash the car near the fan. If one side of the fan isn't spinning when the AC is on, it's probably the AC system being lazy and not activating, especially when the weather isn't hot. However, you need to be extra cautious if the main fan stops working. In summer traffic, the temperature gauge can spike quickly. I just replaced the entire fan assembly this week, and the mechanic warned that delaying the repair could lead to overheating.
After more than 20 years in auto repair, I've seen it all. This issue is most likely caused by the control module. Nowadays, fans are all computer-controlled dual-speed systems. If the vehicle speed sensor goes bad, the fan starts acting up. Another common culprit is a burnt-out fan resistor – last year Old Li's Focus overheated precisely because of this. During inspection, pay special attention to connector corrosion; plugging and unplugging it 3-4 times can scrape off the oxidation layer. Of course, the easiest solution is hooking up a diagnostic scanner to read trouble codes – far more reliable than our old-school method of poking relays with screwdrivers.
Last time I helped my neighbor check his car, it turned out the fan wiring harness was chewed through by mice. For this kind of single-side non-rotation issue, you need to diagnose case by case: For dual-fan models, it's mostly a failed motor - listen for a sandy sound from the fan bearing to confirm. When an electric fan stops working, always check the temperature difference between the upper and lower radiator hoses first - if there's significant difference, the thermostat might be acting up. My old car once had a loose fan connector, and simply reconnecting it tightly fixed the problem. I recommend long-distance drivers always keep some spare fuses for emergencies.
