Having your car's air conditioning system break down can be extremely inconvenient, especially if this happens in the heart of summer when you need it the most. There are different reasons behind auto AC-breakdown, some of which result in complete loss of function and some which impair cooling or delivery of cool air into the vehicle.
Some AC issues are easy to identify and fix, but many require specialised tools and computerized testing, necessitating the intervention of a qualified professional. The article below gives preliminary troubleshooting tips for various components so that you can solve them or effectively describe what's going on to you auto AC technician.
The condenser sits right in front of your radiator and is especially prone to clogging. This problem is easy to solve on your own, and it doesn't require you to remove the condenser in order to reach it. All you need to do is use a garden hose with moderate to high water pressure and directly spray the louvres on the grille. Focus on the lower parts, which are more prone to collecting contaminants such as road salt. Be careful not to pour water in other parts of the engine.
2. Cabin air filter
Every car is fitted with an air filter through which air flows from the AC system under the hood into the cabin. If your AC system has reduced airflow and turning up the fan produces too much noise, you may have an air filter problem. The same applies to persistent, untraceable bad odour in the cabin.
You will find this filter in your glove compartment, under the hood or under the dashboard of your car (you can search your car model online to find out exactly where). Once you find it, pull out to see if it's clogged – it will be full of debris. Carry the filter to an auto shop and find a replacement filter to fix in its place.
To prevent unanticipated breakdowns, replace your air filters every 19,000-24,000 km, depending on the recommendations in your owners' manual. People in heavy traffic or dusty areas should do so more often.
The AC compressor turns low-pressure refrigerant into a high-pressure refrigerant by raising its temperature (using heat drawn from your cabin). The refrigerant then passes to the condenser where its original temperature and pressure is restored by releasing heat to the atmosphere.
The compressor relies on your car's serpentine belt to run, so if the belt isn't spinning, it should be replaced. If the compressor is turning but still not working, there could be a problem in the pistons, clutch wire or interior seals (the latter happens when oil runs low). Low refrigerant levels and the wrong clutch oil can also lead to compressor failure. This is a more complex problem that should be handled professionally.
4. Condenser fan
If your AC is on, but there isn't any air flowing from the vents, there may be a problem with the fan's system including fan motor, temperature sensor, relay or control module. The condenser fan are found under the hood, and it works to prevent the condenser from getting hot. In most cases, burnt wiring or corrosion in the relay wire are responsible for fan failure. Relay replacement should resolve this problem.
If there's air flowing but it's unnaturally warm for your temperature setting, your car overheats if you leave the AC on with the engine idling or you smell something burning, get your AC system inspected to prevent damage to your car components from overheating.