What are the reasons for the rear air vents not blowing hot air?
2 Answers
The reasons for the rear air vents not blowing hot air are: 1. Poor opening due to a faulty valve in the rear air vent; 2. Unreasonable design of the air duct; 3. Damage to the air duct pipeline; 4. Blockage in the air duct or the air filter. The rear air vent is a comfort feature, with one or more air conditioning vents located near the rear seats of the vehicle, sharing the same compressor as the front air conditioning, allowing for independent adjustment of the airflow volume. The solutions for the rear air vents not blowing hot air are: 1. Use a tool to gently pry open the valve or have it repaired at a maintenance shop; 2. Turn the fan to maximum speed to increase the flow rate of hot air; 3. Visit a 4S shop or maintenance shop for inspection and replacement of the air duct; 4. Disassemble the pipeline and clean out any debris, and regularly check the condition of the air filter.
Just fixed this issue. I think the main reasons for the rear vents not blowing hot air are a clogged heater core or low antifreeze level. The engine's heat is transferred to the heater core via the antifreeze to produce hot air; if the core is clogged, the heat can't get through, and the rear will blow cold air. My car had this issue last time, and the passengers all complained about the cold. It could also be insufficient antifreeze causing poor system circulation or a faulty thermostat valve that can't control the airflow. For a simple check, inspect the antifreeze reservoir level in the engine bay to see if it's between the marked lines—top it up if it's low. But more commonly, it's a clog, especially in older cars where dirt builds up easily—this requires professional cleaning or part replacement. It's dangerous in winter; passengers could get frostbite, so don't delay. Regularly check the cooling system to prevent these issues.
