What is the reason why the Audi A4 air conditioner only blows air but does not cool?

[OAlexis]

Audi A4 air conditioner only blows air but does not cool due to a lack of refrigerant. The following are detailed explanations and solutions: Dirty condenser: The purpose of cleaning the radiator and condenser is mainly for heat dissipation. In spring, poplar and willow catkins sticking to the condenser can cause issues such as excessively high engine temperature or poor air conditioning. Solution: Clean the radiator or condenser. Damaged air conditioning compressor, throttle valve, or expansion valve: If the low pressure is high and the high pressure is low, the compressor needs to be replaced. Malfunctions in the expansion valve and throttle valve directly lead to poor air conditioning. Solution: Replace the air conditioning compressor or throttle valve.