How to diagnose and fix your car's broken air conditioning

After a few years of use, a car’s aircon could find itself stumbling or struggling to keep the cabin cool on a hot day. Even if you crank the cooling level to the maximum, it doesn’t seem to register, and all you get is warm air. 

It could be that your airconditioning system is in need of repair or is in need of a good clean. Taking care of your air conditioning system is a part of general vehicle maintenance and should not be overlooked. Either way, here’s how to diagnose and possibly fix your ailing airconditioning system. 

The first thing that you may notice with your airconditioning system is that the fan isn’t getting any stronger. In order of simplicity, these are the possible fixes and affected parts 

Cabin Filter 

If you go to your blower’s max setting, and you can hear the fan whirring away but no air is coming through, then it could be that there is an obstruction in the pathway of air. The common and most obvious fix to this problem is to change out your cabin filter. You may find this part behind the glovebox of your car, and replacing it should be a simple fix. Usually, if your cabin filter is black, or has a lot of debris in it, it needs to be changed. 

Ducts

If you’re still not getting the necessary air speed after changing the cabin filter, it could be that your ducts are obstructed with dust or debris. This won’t be that easy of a fix, so it would be best to get your car checked out by a professional since you will have to take a few things apart. After that, cleaning the ducting should be easy enough. 

Blower motor 

If you’ve done everything prior to improve your airspeed, then it could be that your blower motor could be broken. This will require you to have it either repaired or replaced. If you hear a motor whirring away when your A/C is on, then it could be that the blower’s blades are in need of replacement. If there is no air coming through and now sound, it could be that the motor is on its way out or needs cleaning or replacement. Again, it would be best to leave this fix to the professionals as you could do more harm than good to your car. 

If your fan is running well after diagnosing and fixing the problems, but the cabin doesn’t seem to be getting any colder, then it is likely that your compressor system is in need of attention. In order of magnitude, here are the fixes and problems that you could encounter. 

Not enough refrigerant

Refrigerant cools down the air before it reaches the cabin. It acts as a coolant and is recirculated in your A/C system similar to the cooling system in your car’s engine. Over time, it can escape from the lines which means that your air conditioning system will not cool as efficiently as before. In 2017, the average car leaks about 11.62 grams or 0.41 ounces per year, and a lack of refrigerant over a long period of time is normal. The simple fix for this is to recharge your A/C system with additional refrigerant using a refrigerant recharging kit. Cars that were produced from 1995 onwards use R134a, which can be bought from some to most hardware stores. If your car was produced prior to 1995, it uses R12, which will require you to bring your automobile to a professional for a refill. R12 A/C systems require recharging more often, since the refrigerant tends to leak out faster than R134a. 

A leak in the lines 

If you’ve recharged your A/C system, but still find that your air conditioning system isn’t working well enough to cool the car a leak could be the culprit behind your system ailing. Inspecting your system for a leak will be harder since refrigerant becomes a colorless gas when it gets out of the lines. There are kits for sale that you can use that will dye your refrigerant a specific color to allow you to see any potential leaks either with the naked eye or with UV light. To fix the lines, you may need to bring it to a professional to diagnose, though there are also leak sealing kits that you can purchase to cover up any holes you may encounter. 

Radiator fans are not working effectively 

Another reason why your A/C system isn’t working properly is with your radiator fans. Your compressor spins near the engine in order to get power from the crankshaft. The compressors runs the refrigerant through your entire system. So keeping it cool keeps your system running. If your radiator fans aren’t blowing air, or aren’t blowing air at a fast enough rate, then your engine could overheat and your compressor could overheat as well. Replace or repair your radiator fans if that is the case. 

Compressor is faulty 

To get this part diagnosed, it would be best to take your car to a mechanic or a professional in order to get it fixed or replaced. Your compressor’s clutch could also be faulty which means that you’re Wear and tear can be the culprit of the breakage, however, lack of use could jam up the lines or the other parts of the component, so use your A/C system regularly, but don’t run it too hard maximize the longevity of your compressor. 

The condenser is blocked or broken

The condenser serves as the heat extractor or exchanger of your system and has refrigerant running through it all the time. Over time, the condenser could stop working due to either a blockage or a breakage. Blockages in the system could happen due to some debris getting logged into the system. Like your car’s air ducts and vents, a good cleaning will do the trick, though this job is best left to the professionals. If it’s been inspected and deemed as broken, however, best to get a replacement unit as a puncture in the compressor often is a cause for immediate replacement. 

If you try and turn on your A/C system, and don’t feel any air going through or any fans spooling up, then it could be an electrical issue that is keeping the switch from making a connection to the system, or faulty wiring. 

Control panel is damaged or dirty 

If the switches are not as tight or the dials aren’t clicking into place like normal, then it could be that your A/C’s control panel is damaged. You will know this right away, and a bit of electrical contact cleaner would help you get this issue sorted out. If your car has a digital controls, or is based in the infotainment system, then you could be looking at faulty wiring. Either way, have a professional sort out the wiring issues. If you’re pretty handy with contact cleaner, you could check the switches to see if they are in working order and clean. 

Faulty wiring or a blown fuse 

Wiring is another factor, and these items could get damaged because of corrosion or perhaps animals such as rats. A severed connection means that you won’t be able to interact with the equipment, so it would be best to get your wiring checked by a professional. If your car has a fuse that is out of commission, the system reliant on that fuse won’t work. Most cars come with spare fuses, so consult your manual as to what fuse goes where.