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Why Your Car’s Air Conditioning Isn’t Working and How to Fix It

Car air conditioning control

Your car’s air conditioning is essential for any summer road trip. When it’s not working, it can result in a long and uncomfortable ride for you and your family. A vehicle’s AC system is complex and has many components, so it’s difficult to determine why the cool air stopped flowing. Here are some reasons why the air conditioning in your car is not working and some steps you can take to repair it.

Signs Your Car AC Is Not Working

In most cases, the AC won’t stop working without warning. Here are a few signs that your car’s air conditioning system might need attention:

  • It makes strange noises and hissing sounds. If you notice a strange rattling sound when you turn on the AC, it may be a sign of a broken condenser or fan belt. You should take your car to a trusted auto centre whenever your car makes unusual noises.
  • It blows warm or hot air. If the air coming out of the vents isn’t cool, it may mean that you need to get the refrigerant topped up or that the expansion tube or refrigerant charging hose is clogged. You may also have a blown fuse or a broken compressor, blower motor, condenser or evaporator.
  • It cycles on and off frequently. Short-cycling is caused by a low-level electrical problem, a clogged air intake system or a dirty cabin air filter.
  • It emits strange odours. If, when you activate the AC, it starts to smell like sweaty clothes, it may be time to change the cabin air filter. The foul smell may also be caused by mould forming on the evaporator case or inside the vents. A burning smell indicates the AC’s electrical wiring is overheating.
  • There’s weak airflow from the vents. If the air isn’t blasting out like it used to, it may mean that you have a problem with your blower or that you need to clean your cabin air filter.
  • You see water on the floorboards. Your AC has a drain hose that directs excess moisture away from the evaporator coils and out the undercarriage. If this hose is clogged, condensation will accumulate in the unit and begin dripping into the cabin.

Car AC Problem Diagnosis and Fixes

Most vehicle cooling systems consist of a compressor, a condenser and dryer, an evaporator, an expansion valve and hoses. If your car AC is not working, it could mean one of these parts has failed. Here are the most common problems and their fixes:

  • Leaking refrigerant. This is the most common cause of AC malfunctions. Refrigerant can leak anywhere along the multiple components, lines and hoses, but leaks are most commonly found near the connection points and seals. It can be difficult to pinpoint the source of the leak, but it can be repaired once it’s located.
  • Low refrigerant. Even without a major leak, you may need to top off your refrigerant levels. Over time your refrigerant levels can get lower due to micro leaks throughout the system. A quick recharge will cool your car down in no time.
  • Blocked condenser. The condenser is responsible for cooling the refrigerant. If it’s blocked or clogged, it’ll be unable to properly cool the refrigerant and cause your unit to blow hot air. This can usually be resolved by physically removing any debris blocking the condenser. If the condenser is internally plugged, you may need to replace it.
  • Leaking condenser. If the condenser is leaking, the only way to fix it is by replacing it.
  • Faulty fans. Blown fuses and cracks in the cooling fans can also cause your unit to blow hot air. Broken fans need to be replaced.
  • Electrical issues. A loose or blown fuse can stop your compressor or blower. Fuses are cheap and easily replaced by a technician. If a fuse is loose, a little jiggle could tighten it and re-establish a connection. A qualified mechanic should address electrical issues and blown fuses.
  • Compressor problems. Lack of use can cause problems with a car’s compressor. The compressor is responsible for pressurizing the refrigerant and keeping it circulating. To maintain your compressor, you should keep your AC system turned on full blast for at least 15 minutes once every few weeks, regardless of temperature.
  • Blocked ducts. There may be an insect or rodent infestation in your vehicle that’s obstructing the ductwork. You can try blowing forced air through the vents and cleaning your air filter.

You should also ensure your dashboard switches and dials aren’t broken.

AC Maintenance for Your Car

A car AC problem may be relatively easy to fix, or it may require a professional diagnosis and repair. Regularly scheduled auto tune-ups can keep your AC functioning properly. During regular maintenance, a qualified mechanic can detect minor issues before they become costly problems.

Vehicle Cooling and Heating Services and Auto Repair in Vancouver

At Minit-Tune & Brake Auto Centres, our technicians are well-trained and experienced in dealing with the climate control and air quality systems of all domestic and foreign makes and models. We have conveniently located auto centres in British Columbia and Alberta. If the air conditioning in your car is not working, contact us today to schedule an appointment.


Minit-Tune & Brake Auto Centres Address Common Issues

Here at Minit-Tune & Brake Auto Centres in British Columbia, we’re always pleased to help our customers get the most out of their cars and trucks. To that end, we’ll add a relevant blog topic from time to time to keep you up to date and getting the most out of your vehicle.