Car AC Only Works At Night – Check Compressor – 2024
Feeling like crying when your car AC blows cold at night but refuses to cooperate during the day, especially when it’s hot, is an understatement. You may find out that the problem is often experienced during hot days if one only runs it in lower temperatures at night.
Low refrigerant, dirty condenser, or inadequate fan cooling could be some of the issues causing this experience.
This post aims to provide insight into why this phenomenon occurs and what measures can be taken to ensure that the system always works at its best.
Why Does Car AC Blows Cold At Night But Not During Day?
- High Ambient Temperature: On warm days, air conditioning has to work more. More heat gets into the car when the outside air gets hotter. This makes it hard for AC to keep the inside cool.
- Refrigerant Leak: One common reason cooling does not work effectively is low refrigerant levels. During the night, this may be unnoticeable since less heat may be required to be removed at lower temperatures.
- Condenser Performance: The condenser should be kept free from blockages by anything since it primarily serves the purpose of releasing heat. This becomes even more critical when the outdoor temperatures are high.
- Compressor’s Condition: This component is responsible for moving the refrigerant through the entire system. If it is weak during the day, it might fail to provide enough cooling but may work well during cooler nights.
- Engine Overheating: When it’s hot during the day and your car is running hotter, this can impact the AC. If the engine gets too hot, it will reduce the effectiveness of the air conditioning system.
- Fan and Relay Functionality: The condenser may not be able to cool the refrigerant well when the fan speed is not working correctly or doesn’t work at all, especially if it’s at a standstill. Additionally, faulty relays could cause inconsistent fan operation.
- Airflow and Engine Temperature: Low speeds at which air is pulled through the condenser reduce cooling efficiency, and problems such as a worn fan clutch also decrease it.
How To Fix Car Ac That Works Better At Night?
Enhance Airflow:
Ensure that the fans pushing air through the condenser are working correctly. Inadequate airflow can reduce the system’s cooling capacity during the day.

Check And Refill Refrigerant:
It is vital to ensure that the system has the correct amount of refrigerant. A professional should do this to prevent leaks and ensure the system is pressurised correctly.
Clean The Condenser:
Dirt may clog up with dust particles, which can block airflow around it, affecting the heat dissipation process and making it inefficient in cooling air down as expected; this is why regular checks should always include cleaning off any debris found within or on top of this unit while at the same time not forgetting those areas that are difficult for one person alone to reach easily, like between fins, among others.
Inspect The Compressor:
If there are signs of wear or failure, have an expert check out your compressor. If it cannot compress the refrigerant well enough, you might need a new one altogether.
Address Engine Cooling Issues:
Check the coolant levels, radiator, thermostat, and water pump to ensure the engine does not overheat, which can indirectly affect the AC performance.
Fan And Relay Check:
Relays that are not working must be replaced. Also, check for proper electric and mechanical fan operation (where applicable). These components must all work correctly for the AC system to function as required.
Professional Ac System Check:
Professional inspection may reveal hidden problems such as faulty AC pressure switches or other electrical faults.
Regular Ac Maintenance
You should replace air filters, inspect belts, and have the AC system serviced on a regular basis to ensure maximum efficiency.
Optimize Car Cooling Habits:
- Recirculation Setting: Instead of drawing in warm air from outside, this feature reuses the already cool air in the car.
- Pre-cool Your Car: When it is sweltering outside, turn on your car’s AC before driving off. This will enable it to cool down faster when you eventually start driving.
- Sun Shades: To help your AC work better, use sunshades that can lower the temperature inside the car by reducing the greenhouse effect.
- Park in Shade: Minimize direct sunlight exposure on your vehicle so as to reduce its dependence on air conditioning for cooling.
Why Does My Car AC Not Work In Hot Weather?
Hot conditions might cause a lot of trouble to your car’s AC system, especially if the temperature is higher outside. When it’s hot, the atmosphere becomes warmer, making it difficult for the air to be cooled down effectively by the AC. The heat could also worsen the situation if there are any underlying issues, such as low levels of refrigerant, a dirty condenser, or even inadequate airflow through the radiator and/or condenser.
Low Refrigerant Car AC Symptoms
- AC blows warm air instead of cold
- The AC intermittently blows cold air
- Hissing sounds from the AC unit (indicative of a refrigerant leak)
- Ice formation on the compressor
Dirty Condenser Car Ac Problems
- Reduced cooling efficiency, especially under strain like high ambient temperatures
- The car may overheat due to reduced heat dissipation from the engine cooling system
- Increased wear on the AC compressor due to it needing to work harder
Car Ac Blows Hot Air During The Day, Cold Air At Night:
This is typically due to the AC system’s reduced efficiency in extreme heat. During the day, the outside temperature and sun exposure can heat the car’s interior and its mechanical components to temperatures that challenge the cooling capacity of the AC system.
Car Ac Works Better At Night, Not During The Day:
At night, the cooler ambient temperatures reduce the thermal load on your car’s AC system, allowing it to perform better. During the day, especially in direct sunlight and high temperatures, the same AC system might struggle if it has underlying issues like a dirty condenser or low refrigerant.

Why Does My Car AC Only Work When It’s Cool Outside?
If your car AC only works effectively when cool outside, it likely struggles with heat dissipation or has insufficient refrigerant. More excellent external conditions lessen the burden on the AC system, allowing it to cool more effectively than in hot conditions.
FAQs:
Why Does My AC Work At Night But Not During The Day?
Intermittent operation of your fan during hot days can often be due to the fan motor overheating. When the motor gets too hot, it automatically shuts off to prevent damage. This typically happens during the hotter parts of the day. To resolve this, you might need to replace the fan motor.
Why Does My Car AC Work In The Morning But Not In The Afternoon?
The most common reason your car’s AC works well in the morning but fails in the afternoon is incorrect Freon levels. Cooler morning temperatures can mask a low Freon level, which becomes apparent as temperatures rise.
Why Is My Car Ac Hot During The Day?
If your car’s AC blows hot air during the day, it’s likely due to a low or leaking refrigerant level. The air cannot be cooled efficiently without adequate refrigerant, leading to warm air output when the AC system is running under the strain of higher daytime temperatures.
Why Does My Air Conditioner Compressor Stop Working In The Afternoon But Work Perfectly At Night?
If your AC system is overcharged with refrigerant, it can lead to excessively high pressures on hot days, triggering the high-pressure switch to shut off the compressor. At night, the cooler temperatures prevent this pressure buildup, allowing the system to run smoothly.
Conclusion
A car’s AC system only working effectively at night clearly indicates strain under high temperatures or potential underlying mechanical issues. By understanding these challenges and implementing the recommended solutions, you can enjoy a consistently functioning AC that provides relief, regardless of the time of day. Remember, proactive maintenance is key to avoiding these issues and ensuring the longevity and effectiveness of your car’s air conditioning system.