Car AC Only Blows Cold Air On LO Setting – fix right now

Drivers could run into a problem where the AC only blows cold air when selecting the “LO” (Low) option. Understanding the causes of this behavior can assist car owners in spotting potential issues and looking into workable remedies to get the AC back to work. 

Disconnect the car’s battery for roughly two minutes to reset the interior temperature sensor. Check if the AC behaves normally after reconnecting the battery, accurately adjusting the cabin temperature on various settings.

This article goes into every aspect of this problem, investigating the potential reasons behind the “LO” setting behavior and offering comprehensive ways to address it successfully.

Understanding the LO Setting:

Regardless of the interior temperature, the “LO” option on the car’s climate control system delivers quick cabin cooling. The AC continuously pumps cold air when the dial is “LO,” emphasizing cooling above heating. This option is beneficial in warm weather or when the interior of the car has been too heated from exposure to the sun for an extended period.

Functioning of the Climate Control System:

Understanding the essential workings of the climate control system in a car is crucial to understanding why the AC behaves this way. The system aims to keep the cabin at the selected temperature when the temperature dial is set to a specific value above “LO,” like 61°F.

This is accomplished by automatically switching between heating and cooling modes based on the difference between the current interior temperature and the predetermined temperature.

How the Outside Temperature Sensor Affects the Car AC?

The ambient temperature sensor, also known as the exterior temperature sensor, is a small electrical device that is normally located toward the front of the vehicle. Its main job is to gauge the atmosphere’s temperature around the car. To efficiently control the cabin temperature, this information is transmitted to the vehicle’s HVAC (heating, ventilation, and air conditioning) system.

How the Outside Temperature Sensor Affects the Car AC
source:vehicle wiadom

The car’s climate control system uses the information provided by the outside temperature sensor to calculate how much cooling or heating is necessary to reach the target cabin temperature. The air conditioner typically operates at maximum capacity to effectively chill the incoming air when the temperature is lower.

However, the climate control system might not get reliable information about the outside environment if the exterior temperature sensor malfunctions or generates false data. As a result, the AC might not operate at its best in higher settings.

The Role of Temperature Differential:

The climate control system integrates a temperature differential to avoid frequent and sudden shifts between heating and cooling modes. To put it another way, the system will only change from heating to cooling (or vice versa) when the interior temperature is sufficiently different from the specified temperature.

Why Car AC Only Blows Cold On Lowest Setting?

1. Interior Temperature Sensor Malfunction:

The car’s climate control system may receive inaccurate signals from an erroneous or broken interior temperature sensor. The system consequently continuously prioritizes cooling, resulting in the AC only blowing cold air on the “LO” setting.

Interior Temperature Sensor Malfunction

2. Electrical Glitch or Calibration Issue:

The accuracy of the interpretation of interior temperature data can be hampered by electrical glitches or calibration issues with the climate control system, which can lead to the AC functioning incorrectly on settings other than “LO.”

3. Control Unit or Climate Control Module Fault:

The behavior of the AC may be affected, leading it to prioritize cooling when set to “LO” regardless of the actual interior temperature if the automobile’s control unit or climate control module has a malfunction or breakdown.

Control Unit or Climate Control Module Fault

4. Outside Temperature Sensor Error:

The outdoor temperature sensor controls the climate control system in some way. If it offers false information, the AC cannot respond to other temperature settings correctly.

5. Coolant or Refrigerant Issues:

The performance of the AC may be impacted by issues with the coolant or refrigerant levels, favoring the “LO” setting to sustain cold air.

Coolant or Refrigerant Issues

6. Blower Fan or Blower Motor Resistor Problems:

The air distribution can be affected by problems with the blower fan or motor resistor, which may impact how the AC performs in various settings.

How To Fix Car AC Only Blows Cold On Lowest Setting?

1. Reset The Interior Temperature Sensor:

  • Disconnect the battery from the car for roughly two minutes to reset the interior temperature sensor. Check if the AC behaves normally after reconnecting the battery, accurately adjusting the cabin temperature on various settings.
  • Have the interior temperature sensor checked and, if necessary, replaced by a competent mechanic if the problem continues.

2. Fix Electrical Hiccups:

  • Speak with a qualified automotive electrician or technician to identify and fix any electrical hiccups or calibration issues with the climate control system.
  • To fix these problems, they might run diagnostic scans and recalibrate the system.

3. Examine The Vehicles Temperature Control:

  • Have a qualified mechanic examine the vehicle’s temperature control module and control unit to look for malfunctions or problems.
  • To restore appropriate AC functionality, replace or repair the control unit or module as necessary.

4. Check Outdoor Temperature Sensor:

  • Check the outdoor temperature sensor for damage or improper installation.
  • To ensure correct temperature readings for the climate control system, calibrate or replace the sensor as necessary.

5. Check Coolant And Refrigerant Levels:

  • Have a qualified mechanic check the coolant and refrigerant levels in the vehicle.
  • The mechanic can fix the system, recharge, or take care of any other coolant- or refrigerant-related issues if there is a leak or inadequate levels.

6. Check Blower Motor:

  • Check for flaws or issues with the blower motor resistor and fan.
  • To guarantee adequate air circulation and AC system operation, replace damaged components.

Factors of “LO” Setting Behavior:

1. Warm Weather Conditions:

Drivers frequently choose the “LO” setting to achieve quick cooling without having to wait for the interior temperature to reach the predetermined degree for cooling mode engagement in hotter climes or locations.

Warm Weather Conditions

2. Parking Under the Sun:

A car’s interior temperature may rise above the dialed setting if left in the sun for a long time. When this occurs, switching to the “LO” setting enables the AC to quickly cool the cabin.

3. Driver Preferences:

Some drivers frequently select the “LO” setting regardless of the weather outside because they like a cooler cabin. It’s crucial to remember that the “LO” setting skips the temperature difference and constantly blows cold air.

Driver Preferences

Solutions for Restoring Normal Functionality:

Consider the following in-depth fixes if the car’s air conditioner only blows cold air on the “LO” level and doesn’t operate as it should at other temperature settings:

1. Verify Temperature Setting:

Check again to ensure the temperature dial is set to the desired temperature above “LO.” Make sure there are no user or accidental modifications.

Verify Temperature Setting

2. Check for System Malfunctions:

To find any underlying problems with the climate control system, do a thorough diagnostic test utilizing the vehicle’s onboard diagnostic system. The behavior of the “LO” setting may be caused by electronic control issues, which this step can help find.

3. Inspect Temperature Sensor:

The outdoor temperature sensor gives the climate control system precise readings. The performance of the AC may be impacted if this sensor is broken or gives false signals. To ensure reliable temperature measurements, have the sensor checked, calibrated, or replaced as necessary.

Inspect Temperature Sensor

4. Seek Professional Inspection:

Consult a certified mechanic or other automobile service expert if the problem continues. They may fully inspect the entire AC system, including ducting, the compressor clutch, the blower motor, and the refrigerant levels. It will make it easier to spot and fix any mechanical or functional issues that might be preventing the AC from operating as it should.

How To Reset Interior Temperature Sensor?

It can be confusing to experience a situation where the car’s AC continuously pumps hot air, save on the “LO” setting. The interior temperature sensor, which gives the climate control system correct readings, may have become harmed if this problem appears after a complete interior cleaning. Resetting the interior temperature sensor can be a good option in certain circumstances. Here is how to go about it:

1. Disconnect the Battery:

Start the reset procedure by unplugging the vehicle’s battery. Find the battery in the car and release the clamp on the negative connection to detach it. When handling the battery, take the necessary safety precautions, such as wearing safety gloves and ensuring no metal objects come into contact with the battery contacts.

Disconnect the Battery
source:car and driver

2. Wait For Approximately 2 Minutes:

After removing the battery, give it around two minutes to fully recharge. Any remaining electrical charge in the vehicle’s systems, including the interior temperature sensor, can dissipate during this time.

3. Reconnect the Battery:

Make a secure connection by reattaching the clamp on the battery’s negative terminal. Verify again that the connections are all securely tightened.

Reconnect the Battery

4. Start The Car And Test AC System:

Start the ignition of the vehicle and let it run for a while. Give the systems of the car time to initialize correctly.

Test the car’s air conditioning system after conducting the interior temperature sensor reset. Change the temperature settings to different values, including the “LO” parameter. Check the airflow from the vents to ensure the AC is operating as it should.

5. Check Interior Temperature Reading:

Check the temperature inside the car with your mid-level MB scanner or the onboard system. Now, it ought to show a value that reflects the actual inside temperature of the vehicle.

Check Interior Temperature Reading


1. Why Is My Car AC Not Cooling At High Speeds?

The two most common causes of defective air conditioning are leaks and compressor difficulties. If your air conditioner is blowing chilly air but not frigid air, the issue may be a clogged filter, cooling fan, or radiator malfunction, or it may just be that your AC needs to be recharged.

2. Why Is My AC Not Cooling Below 75?

You should check if the evaporator coil is frozen and your air conditioner won’t chill below 75. If so, you’ve identified the issue. Usually, a dirty air filter is to blame for this, as it can obstruct airflow and result in frozen coils. To fix the problem, see whether your filter is dirty and replace it.


No matter what the interior temperature is right now, the “LO” setting on the car’s climate control system is intended to deliver quick cooling. This feature comes in handy when it’s hot outside, or the automobile has been left in the sun for a while. However, if the car’s air conditioner only blows cold air on the “LO” level and performs poorly at other temperature settings, it could be a sign of more severe problems with the AC system. Understanding the root reasons and putting the proper fixes in place will help car owners get their AC back to working normally so they can drive comfortably in any weather. Remember, a thorough evaluation and appropriate treatment of the problem require professional assistance from qualified technicians.

Video Guide:

Also Read:

Similar Posts