7 Common Car AC Issues and Solutions
In Arizona, you may use both your heater and car air conditioner on the same day depending on when it’s hot. Afternoons can get quite muggy without that cool blast from your air conditioner; however, if it does go out during this time of year it won’t be a major catastrophe; however, being without air conditioning for too long could mean higher temperatures that won’t go away! Most people struggle with diagnosing their car’s A/C problems; there are several reasons why your unit may stop working; here are the most frequent causes and how they’re fixed:
The Air Conditioning system consists of several elements, such as a compressor driven by an engine; an expansion valve to regulate refrigerant flow; and two heat exchangers: the evaporator and condenser. Refrigerant is a fluid that changes from liquid to gas before returning back to liquid form throughout the system.
Problem: No Cold Air from AC
Most often, this issue is caused by a refrigerant leak. Your air conditioning components rely heavily on refrigerant to cool the vehicle; without enough of it, other air conditioning components won’t function properly. Leaks can happen at any time but are most commonly due to holes in connections, hoses, compressors, condensers or ruptured evaporators. Unlike oil leaks which are easy to identify; refrigerants naturally evaporate when exposed to environmental elements.
Solution: An experienced automotive technician must add fluorescent leak tracer dye and refrigerant to the system. Running the air conditioning will allow them to identify the leak with a blacklight, then they can begin repairs, evacuate it and recharge to blow cold air once again.
Problem: No Air Coming From Vents
It may not be as obvious an issue as hot air coming through the vents, so a technician must first rule out other potential causes by inspecting several components. They may begin checking for:
A blown fuse or bad relay – If the ventilation fuse blows, power to the blower motor is lost, preventing air from blowing through vents. Similarly, a defective relay may also be to blame as it takes small electrical current and uses it to regulate larger current needed for ventilation.
Damage to the blower motor or blower resistor – The blower motor pushes air through vents in cars, much like a fan does at home. When these malfunction due to wear or age, you won’t be able to make use of them. Conversely, blower resistors work together with the motor in order to control how much air comes through (low, medium, high) according to your preference.
Blocked Air Intake – Vehicles have two areas where air enters the vehicle: vents on the lower half of the windshield and recirculated air from inside. If either intake area becomes blocked due to clogged filters or other debris, little or no air may come through your vents.
Damaged belts and hoses – The air conditioning system is equipped with numerous hoses and belts that operate it. Any leak, detachment, or blockages will prevent proper airflow from the vents.
Solution: Start by replacing fuses and/or the relay. If this doesn’t solve the problem, consult an A/C technician to test other components related to ventilation system performance; repairs or replacement may be needed.
Problem: Air Is Cool But Doesn’t Get Cold
Most often, this problem is due to low refrigerant levels. Without enough coolant in the system, pressure on the clutch is reduced which prevents it from activating the compressor’s cycle. On the other hand, if there is sufficient refrigerant present it could also be indicative of:
Blocked or Failed Condenser – The condenser is the device responsible for taking refrigerant from its gaseous state and returning it to a liquid one. If there’s an obstruction in the condenser or damage has occurred, cold air won’t come through the vents.
Failed Clutch Switch – If this component fails, the air compressor will be unable to function and prevent condensing liquid refrigerant into gas.
Solution: A technician should inspect these major components for any signs of blockages, damage or malfunction and replace them as necessary.
Problem: Your Air Conditioner Smells Like Mildew
When you turn on your air conditioner and the pungent smell of mildew hits your nostrils, it’s likely due to bacteria growth in the system. This is particularly common with vehicles that rarely use A/C, are older, or use maximum setting due to extra moisture present. Bacteria, mold, fungi and other microorganisms may develop behind dashboards on evaporators which produces an unpleasant odor from vents.
Solution: Air filters can accumulate dirt, water, dust and other pollutants over time which may create an odor. Replacing your air filter should help combat this problem; however if that does not eliminate all traces of stench then a technician may need to add anti-bacterial solution into the evaporator area in order to eliminate mold and other pollutants from the system.
Problem: Car Air Conditioner Makes Noise When On
Anytime your car makes a noise that wasn’t there before could be indicative of trouble. Air conditioning systems tend to be quite quiet when running, so when you hear unusual sounds like rattling or banging when turning on the air conditioning system, it’s normal to feel nervous about what could be causing the issue. It could simply be leaves or other road debris blocking the unit and creating all sorts of odd sounds; or it could indicate major component failure such as bearing wear causing grinding or squealing noises; similarly rattling could indicate clutch failure in compressor.
Solution: Continued use of your air conditioning may only make things worse. Take your vehicle to a reliable technician for inspection to detect whether any major components are malfunctioning and require replacement. A detailed examination can identify whether this is necessary.
Problem: Water Seeping Through the Floorboards
What could cause this?
Bacteria accumulates on the air conditioner’s evaporator coil in its heater box located under your dashboard, mixing with condensation from the coils. Over time, this slimy film forms on the fins of your A/C and gives off a musty odor. Over time this buildup may clog the drain line – a rubber hose that starts in the heater box, travels through the floor to your undercarriage to remove moisture buildup. Once plugged, water from condensation seeps out onto the vehicle’s floor – typically on passenger side – until eventually you see water seepage onto floorboard surfaces around it.
Solution: If you find your vehicle’s floor damp, don’t delay in taking it to an automotive center for immediate repair. A technician will need to identify what has caused the drain line to become clogged and will either repair or replace the hose as necessary.
Problem: Air Conditioning Goes From Cold to Hot
When driving and the air temperature suddenly changes from comfortably cool to unbearably hot, you know there’s an issue. It could be that the expansion valve that dispenses refrigerant to your evaporator has failed; a blocked expansion valve prevents coolant from reaching the evaporator and, if moisture is present, may even freeze due to lack of circulation.
Solution: Make sure the air conditioning system is cold. A certified technician should then test the pressure of the system and check components for blockages or malfunctions.
No matter the symptoms your air conditioning system may be experiencing, a qualified automotive technician has the knowledge and skill to accurately diagnose car AC problems and restore it back to full operation. Need service on your A/C? Visit Sun Devil Auto near you for solutions to all of your air conditioning troubles.