Car AC Sometimes Works Sometimes It Doesn’t

Many car owners experience the issue of an air conditioning system that works intermittently. This involves the AC unit turning on and providing cool, comfortable air for a few minutes before shutting off again. This repeated cycle can make trips in a vehicle very uncomfortable and unpleasant. If you are one of these drivers experiencing this problem, then understanding why it happens and how to fix it is essential knowledge. In this article, we will discuss common causes for an AC that turns on and off intermittently as well as possible solutions to this issue so that you can diagnose your own situation or find suitable remedies for your car’s AC.

See also: How to Trick a Mass Air Flow Sensor?

What should I do if my car’s air conditioner is working intermittently?

What should i do if my car AC works intermittently
What should i do if my car AC works intermittently?

When experiencing an intermittent AC issue with a car, the first step is to document any related events so that it can be explained to a mechanic. This will help them narrow down the cause of the problem and provide an appropriate solution. For those who are comfortable working on cars, they may choose to diagnose their own AC system as it has many components which make up its complexity. For individuals without knowledge or experience in this area, taking their vehicle into a mechanic is recommended in order for them to receive professional assistance.

Can I solve this Car Air Conditioner Sometimes Works Sometimes Doesn’t problem myself?

Can I solve this Car Air Conditioner Sometimes Works Sometimes Doesnt problem myself
Can I solve this Car Air Conditioner Sometimes Works Sometimes Doesn’t problem myself?

It is sometimes possible to diagnose and repair car AC problems without the help of a professional. To begin with, owners should take note of any strange occurrences they notice while operating the air conditioning such as cycling on and off, failing in stop-and-go traffic or on highways, and odd smells when it goes off. From there, owners can check under the hood for leaky parts that may be easily repaired at home. If these steps do not work, further investigation may be required from an auto technician:

  • Check status of AC control panel (is it working correctly?)
  • How long were you driving when AC started cycling?
  • Does it fail in stop–and–go traffic or highway?
  • Does the AC fail at times or cycle on & off?
  • Are there strange smells when AC goes off?​

Car AC Sometimes Works Sometimes It Doesn’t Causes and How to Fix It

Car AC Sometimes Works Sometimes It Doesnt Causes and How to Fix It
Car AC Sometimes Works Sometimes It Doesn’t Causes and How to Fix It

Lack/overcharged refrigerant

Lack overcharged refrigerant
Lack overcharged refrigerant

Lack/overcharged refrigerant R-134a is a liquid refrigerant used in vehicles manufactured after 1996. It is essential for proper functioning of the air conditioning system, requiring an exact amount to be present. When there is too much or too little of this substance, it can lead to a variety of problems including reduced cooling efficiency, increased fuel costs and other performance issues. It’s important that owners ensure their vehicle has the correct amount of R-134a so their air conditioner runs as it should.

Diagnosing Lack of R-134a

When diagnosing lack of R-134a, it is important to look for signs such as white emissions from the hood, a hissing/clicking sound and smell of Freon. Grease-like liquid around AC parts can indicate refrigerant leaks which cause the R-134a level to drop. In addition, a low gauge reading can also signify low refrigerant levels. These symptoms are indicative of malfunctioning AC and failure of clutch engagement. An AC manifold gauge is necessary in order to properly diagnose this issue.

What to do

It is generally not recommended for individuals to try and recharge their system without professional assistance. A technician should be called upon to locate any possible leaks, as it can be difficult to pinpoint the source of a leak on one’s own. After addressing the issue of any potential leaks, the technician will then go about replacing the correct level of R-134a in order to prevent overcharging of the system. This ensures proper safety measures are taken when recharging a car’s air conditioning system.

Diagnosing an overcharged AC

In order to diagnose an overcharged AC system, technicians must first identify signs such as a slow or stopped cooling process and higher pressure readings. This is typically due to too much R-134a in the air conditioning system which does not allow for enough room for expansion of gases. As a result, the air compressor may also be unable to handle these increased pressures leading to an even higher temperature.

What to do

Unfortunately, it is not possible for an individual to safely fix an AC that has been overcharged with R-134a. This is due to laws and regulations surrounding this particular gas, which can be harmful to the environment if mishandled. The only way to correctly remove excess R-134a from an AC system is through the use of specialised equipment operated by a trained professional. The excess fluid will then be collected into an airtight container ready for reuse or recycling.

Failed AC compressor/ compressor clutch

Failed AC compressor compressor clutch
Failed AC compressor compressor clutch

A failed AC compressor means that the air refrigerant is not being pressurized, resulting in high cabin temperatures and other issues. Signs of a bad AC compressor include moisture leaks, tripping circuit breakers, loud noises from the compressor, broken suction lines, oil leaks and physical damage. Furthermore, if your cabin temperature keeps on fluctuating or the clutch is stiff then it’s an indicator of potential problems with the air compressor. To inspect for these signs and save money on repairs be sure to check for:

  1. Moisture leak
  2. Tripping circuit breaker
  3. Loud noise from the compressor
  4. Broken suction lines
  5. Oil leaks & physical damage
  6. Fluctuating cabin temperature
  7. Stiff clutches

What to do

If the conclusion is that the air compressor of a vehicle’s AC system has failed, then changing it is necessary to restore proper functioning. DIYers may be able to change out the compressor themselves; however, as this is a complex procedure, it is recommended to seek assistance from an auto mechanic with experience and qualifications in performing this kind of repair work.

Dirty cabin air filter/ fan housing

Dirty cabin air filter fan housing
Dirty cabin air filter fan housing

The cabin air filter and fan housing of a vehicle should be regularly checked for dirt or clogs, as these can cause the AC to work harder or not at all. Fortunately, replacing the cabin air filter is an easy task that requires only a screwdriver; it is usually located behind the glove box. The same applies to cleaning a dirty fan housing; it necessitates removing the fan from the engine compartment and using degreaser on it before putting it back in place. With just a few simple steps, any driver can ensure their car’s AC is running optimally.

Faulty thermostat

Faulty thermostat
Faulty thermostat

A faulty thermostat can have a significant impact on a vehicle’s air conditioning (AC) system. Thermostats are part of the car’s computer system, which helps regulate temperature and ensure smooth operation of the AC compressor. When this system malfunctions, it could lead to overheating in the engine and erratic changes in temperature readings on the dashboard gauge.

If you suspect that your vehicle is suffering from a failing thermostat, there are several signs to look out for:

  • Overheating engine
  • Erratic temperature changes on dash gauge
  • Coolant leaking

To properly fix these issues, one should replace their vehicle’s thermostat, flush their cooling system and top off their coolant reservoir. Although most DIYers will be able to do this themselves; it is recommended that they bring it into an auto repair shop for proper diagnosis and repairs if necessary.

Blocked evaporator drain

Blocked evaporator drain
Blocked evaporator drain

The evaporator in a car’s AC system is an important component of keeping the air inside the cabin cool and comfortable. When the evaporator drain tube becomes clogged, it can cause water to accumulate around the foot wells and create a sloshing sound when making turns. Fortunately, there is an easy way to unclog this tube if needed.

To remove a block from an evaporator drain tube, you will need one foot of metal wire and appropriate jacking equipment for your vehicle. Once your car is parked on a flat surface with enough light, use the jack to raise it off of the ground before adding jack stands for extra safety. Then locate the small rubber hose underneath that connects to the engine and detach it so you can access where any potential clogs may have formed inside. With one end of your metal wire shaped into a hook, carefully push it into this opening while twisting until you reach any potential blockage that needs removal. Allow water to drain out before reattaching the drain pipe and lowering your car back onto its wheels using jack stands or other jacking tools as necessary. Take it out for another test drive afterwards just to be sure everything is working properly again!

5 Tips To Unblock An Evaporator Drain Tube

  1. Park on flat surface with adequate lighting
  2. Use emergency brake & appropriate jacking equipment
  3. Locate small rubber hose connected underneath car
  4. Push hooked metal wire into pipe while twisting gently
  5. Reattach hose after removing blockage & lower vehicle

Bad ac control unit

Bad ac control unit
Bad ac control unit

When it comes to air conditioners, the control unit plays a crucial role in regulating all the functions of an AC system. This unit can differ between car brands, models and even years, yet there are some general symptoms that indicate a failing control panel.

Some common signs include inconsistent cooling where AC seems to struggle to maintain cabin temperatures; uneven air distribution; difficulty controlling fan speed; problems using the button for engaging the air compressor and intermittent re-circulation of air on hot days. If any of these issues occur, then you will need to replace your failing control panel with one that fits your specific vehicle year and make. To ensure proper installation and functioning of this new part, refer to both the guide on your new control unit as well as your vehicle’s manufacturer’s manual.

5 Symptoms Indicating A Failing Control Panel:

  1. Inconsistent cooling where AC struggles to maintain cabin temperatures
  2. Uneven air distribution
  3. Inability to regulate fan speed
  4. Problems using button for engaging air compressor
  5. Intermittent re-circulation of air on hot days

Leaking around the compressor shaft seal

Leaking around the compressor shaft seal
Leaking around the compressor shaft seal

Mechanics and advanced DIYers are typically the best equipped to replace a compressor shaft seal due to its location. This is because quite often, refrigerant can escape through the compressor shaft seal – especially if it is old, worn and of a second-rate quality. Unfortunately, this type of leak is one of the most challenging ones to detect.

This is primarily because the shaft seal sits behind the clutch hub and under the dust cover in many vehicles, making it difficult for an untrained eye to spot. To diagnose such an issue, one needs to inspect the compressor shaft seal visually or use UV dye injection in order to identify any leaks from this part accurately. Once identified, replacing it should be done by a professional as soon as possible in order for your vehicle’s AC system to work effectively once again.

Broken electric blower motor

Broken electric blower motor
Broken electric blower motor

The electric blower motor is an essential part of a car’s AC system. It is responsible for blowing air through the vents and can become faulty over time, leading to a reduced airflow from the vents or lack of airflow altogether when the AC is on. Common symptoms that suggest this component has worn down include low airflow, smoke coming out of the vents, and fan running only at certain speeds.

Common causes of a broken electric blower motor are short circuits, bad switches, and fluid leaks. Repairing this issue requires taking apart much of the interior components which should not be attempted by those inexperienced in auto repair due to its complexity. It’s important to identify if this is indeed causing your issue before any repairs are done as doing so will save both time and money in the long run.

Here is a listicle highlighting what you need to know about electric blower motor breakdown:

  1. Low airflow from the vents or lack thereof when AC is on are common signs it’s malfunctioning
  2. Causes usually involve short circuits, bad switches or fluid leaks
  3. Smoke may blow out of your vents if it’s particularly damaged
  4. Not suitable for beginners in auto repair to undertake themselves
  5. Identifying problem properly beforehand will ensure more effective solutions

Incorrect temperature sensor or pressure sensor

Incorrect temperature sensor or pressure sensor
Incorrect temperature sensor or pressure sensor

The ambient temperature sensor plays an important role in the operation of a vehicle’s air conditioning system. This sensor is responsible for calculating the environment’s temperature and relaying it to the vehicle’s computer as a reference for calculations. When the temperature sensor fails, it can give an incorrect reading that will cause uneven cooling.

Replacing this component requires some basic tools and technical know-how. It is recommended that safety gear such as gloves and safety goggles be worn when performing any maintenance or repair on a car. The following list outlines what is needed to replace an incorrect temperature or pressure sensor:

  • Gloves
  • Safety goggles
  • Socket set
  • Plier assortment
  • New ambient temperature sensor

Once all necessary items have been gathered, disconnecting power from the battery by removing its cable, locating the faulty sensor at the front of engine bay, disconnecting wiring from old components, installing new parts and reconnecting power are all steps required to ensure successful completion of this replacement job. Following installation, one should take their car out on a test drive to check if AC functions correctly with different temperatures outside of cabin space before considering task complete and giving yourself pat on back!

See also: DTC B1493 Hyundai

What about an incorrect pressure sensor?

What about an incorrect pressure sensor
What about an incorrect pressure sensor?

When an incorrect pressure reading occurs in an air conditioning system, it can cause the AC to rapidly turn on and off. This is because the pressure sensor notifies the AC that it needs shut down due to overheating or may prevent it from turning on altogether. To diagnose a malfunctioning pressure sensor, one must use a low-pressure gauge with a refrigerant recharge kit. If the reading of this gauge falls below 56 psi, then there are likely problems related to the pressure sensor.

If intermittent heating still persists after diagnosing any issues with the pressure sensors, it’s best to take your vehicle to a professional mechanic for further verification. The mechanic will be able to test electrical connections and scan for health status of these sensors by using an OBD2 scanner if necessary. Replacing faulty switches should also be easy; all you need is knowledge about which switch (high or low) isn’t working properly before disconnecting its battery, locating and replacing old ones with new ones accordingly.

See also: Code P219A – Bank 1 Air/Fuel Ratio Imbalance

How much does it cost to repair AC problem?

How much does it cost to repair AC problem
How much does it cost to repair AC problem

The cost to repair an intermittent AC varies depending on the cause of the problem. It is important for a car owner to investigate and determine the source of the issue before taking their vehicle to a mechanic in order to ensure that they know what needs to be done. Minor compressor repairs typically range from $170 – $370, while more complex issues can cost up to $4000. An AC recharge usually costs between $100 -$150, whereas clutch repair or replacement may cost between $200-$750. Taking proactive steps early on by diagnosing and addressing potential problems can help save money in costly future repairs.

When it comes to cars, a broken air conditioner can be an annoyance that many drivers would rather do without. The car AC sometimes works and sometimes doesn’t, which can be very frustrating. Fortunately, understanding why this happens and how to fix it is possible with the right information.

See also: P1035 Code Ford, Chevy, Toyota, Jeep

The causes of an intermittent car AC could range from something easy to fix like low refrigerant levels or more complex issues such as electrical problems or even damage to the compressor system. In order for these issues to be addressed properly, taking the car in for service at a repair shop such as Lexus dealer service department may be necessary. However, one should take action immediately upon noticing any signs of malfunctioning within their vehicle’s AC system in order to prevent further inconvenience down the line. With proper care and maintenance, your car’s air conditioning should not give you any trouble going forward!

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