Why is the air conditioning not blowing hot air when heating?

[VanCamila]

The reasons why the air conditioning does not blow hot air when heating are: 1. The thermostat is damaged, causing the cooling system to enter the large circulation prematurely; 2. The air filter is dirty and clogged, affecting the heating effect; 3. The heating control button is damaged and cannot transmit the corresponding heating supply signal; 4. The small heating tank is blocked, preventing the coolant from passing through it; 5. The water pump impeller is damaged or slipping, resulting in insufficient flow through the small heating tank. The correct method for using the air conditioning heating is: 1. Turn on the heating 8 to 15 minutes after starting the car; 2. First use the external circulation to expel the cold air inside the car, then switch to internal circulation after 2 to 3 minutes; 3. Switch to the heating mode; 4. Adjust the air conditioning to the appropriate gear and adjust the air outlet direction; 5. Direct the warm air towards the front and the feet.

[LeNaomi]

I've been repairing cars for many years. If the car's air conditioning isn't blowing hot air, the issue could be in several areas. The most common is a coolant problem—if the radiator fluid level is too low or the water pump is broken, hot air won't blow because the engine heat can't transfer to the AC system. Another issue could be a clogged heater core, where debris blocks circulation, resulting in cold air. If the thermostat fails and can't regulate temperature, it might still blow cold air. The fan can also be troublesome—if the motor is stuck or there's poor wiring contact, hot air won't reach the cabin. Additionally, a faulty sensor or control module can cause the AC to malfunction. If this happens in winter, don't delay—first check the radiator fluid by opening the hood and looking at the transparent reservoir. If the level is below the standard line, add some antifreeze. If it still doesn't heat up, take it to a professional repair shop immediately to avoid freezing while driving, especially on highways. Regular maintenance is key—check the AC system every six months to save a lot of trouble later.

[VanJaxson]

I'm an experienced driver and have encountered the issue of no hot air from the AC, which is quite annoying. It might be due to insufficient coolant or the heater being clogged with dust, preventing warm air from coming out. Driving in winter without heating is miserable—the car gets freezing cold, affecting driving safety, like making the steering wheel stiff from the cold. I suggest doing a quick check yourself first: after starting the car, see if the engine temperature gauge rises normally; if it does, the issue might be internal to the AC system. Sometimes, small components like the thermostat valve fail, or the fan stops working. It's best not to attempt repairs yourself—take it to a nearby 4S shop for professional debugging. Remember to change the coolant regularly, once a year, to prevent such issues. If the problem occurs on a long trip, open the windows for ventilation and drive slowly to the nearest repair shop. Safety first.

[AvaMarie]

I've had similar issues with my own car where the AC couldn't blow warm air properly, and there were quite a few problems. Insufficient coolant is the most common cause—try topping it up, which usually helps. Blockages with impurities in the heater core or a faulty water pump can also result in cold air. A malfunctioning thermostat losing control accuracy or dirty sensors misjudging temperatures can be culprits too. As for the fan—motor jamming or damaged wiring—can affect airflow. I recommend a DIY check first: pop the hood to see if the coolant reservoir level is low; listen for any unusual noises from the fan. If nothing seems off, quickly contact a repair shop for professional diagnostics, like pressure or current tests. This issue is especially dangerous in winter, as low cabin temperatures can distract drivers. Regular maintenance, such as changing the AC filter every six months, helps avoid such hassles.