The reason why the Passat B5's heater becomes cold after a minute or two after it is turned on is that there is a problem with the heat-cooling conversion motor.
When the air conditioner of the Passat B5 is on, there will be two streams of wind blown into the car by the air conditioner. One is the warm air from the heater water tank, and the other is the cold air from the air conditioner. After mixing, adjust to the appropriate temperature according to the set temperature value. When there is a problem with the hot and cold conversion motor and the cold air inlet volume is out of control and too much air enters, the warm air will not be hot.
Solution:
1. Replace the hot and cold air conversion motor, paying special attention to its flap. You need to lift the meter when replacing it. Improper operation will cause many problems, so you need to be careful when replacing it.
2. When turning on the warm air, adjust the temperature to the highest level. When the economy button (ECON) is pressed, the air conditioner will not cool down. The cold air mixed in is natural wind, which can maintain the heat of the air conditioning air and the temperature inside the car will be higher.
Extended information:
Causes of Passat B5 hot and cold conversion motor failure:
1. The heater water tank is blocked or there is an actuator problem. The principle of the car's warm air is to use a blower to blow the heat from the small warm air water tank into the cab. If the air volume is insufficient or the hot and cold air distribution is not good, the heat from the small warm air water tank cannot be dissipated, causing the temperature of the warm air to be low. rise.
2. The damper inside the air duct cannot be switched in place, resulting in the inability to completely open the hot air and close the external circulation.
3. The heating control mechanism is damaged. If the two water inlet pipes of the heating water tank are overheated, it means there is a problem with the heating control mechanism.
People's Daily Online - Why is it so cold! It’s really terrible if the air conditioner heater is not hot in winter
Baidu Encyclopedia-Passat B5
Baidu Encyclopedia-Car Heating System