What is the reason for the car air conditioner not cooling and then cooling again after restarting?
4 Answers
Car air conditioner not cooling and then cooling again after restarting is caused by: 1. Problems with the air conditioner's liquid storage and drying tank; 2. The compressor protection device tripping; 3. Radiator blockage. The solutions for the air conditioner not cooling and then cooling again after restarting are: 1. Replace the air conditioner's liquid storage and drying tank; 2. Secure the compressor protection device from tripping; 3. Clean the radiator. The functions of a car air conditioner are: 1. To cool, heat, ventilate, and purify the air inside the car; 2. To provide a comfortable environment for passengers, reduce driver fatigue, and improve driving safety. Maintenance methods for car air conditioners: 1. Clean the air conditioner vents promptly; 2. Maintain the air conditioner condenser in a timely manner; 3. Clean or replace the air conditioner filter element promptly.
Last time I encountered this issue, it was due to an aging relay. That small black relay in the air conditioning control box—its contacts can become unreliable after prolonged use, much like an old-fashioned switch that might only work three times out of ten presses. When you restart the car, it barely makes contact again, and the AC kicks in. Don’t underestimate this problem. Once, I was stuck on the highway in the middle of summer, and the AC kept cutting in and out—I nearly got heatstroke. My advice: head to an auto repair shop soon and spend a few bucks to replace the relay. While you’re at it, have the mechanic check if the circuit voltage is stable, as fluctuations can also cause the relay to act up.
The compressor electromagnetic clutch is probably acting up. This component is responsible for transmitting engine power to the AC compressor, but when its coil or bearings wear out, it starts working intermittently. Engine RPM changes during restart might temporarily reset it. My decade-old car had this exact issue - initially, slapping the hood would jolt it back to life, but eventually it failed completely. Easy diagnostic method: Have a mechanic listen for the 'click' engagement sound when activating the AC. No sound or intermittent clicking usually confirms the problem. Replacing just the clutch assembly costs significantly less than a whole new compressor.
Temperature probe malfunctions are the most frustrating. For example, if the evaporator temperature sensor gets covered in dust or the probe position shifts, it can misjudge the temperature and cause the compressor to shut down prematurely. After a restart, the system resets and works normally again. My old car had this issue last year—the mechanic blew out the sensor with an air gun and recalibrated the parameters using a diagnostic computer. He mentioned that some newer cars now use a dual-sensor design, where one can still function as a backup if the other fails. Regularly cleaning the AC ducts can prevent this problem, as excessive condensation can also interfere with the probe's readings.
