AC Blows Hot Air On Passenger Side: Why?

Is your car’s AC acting weird by blowing hot air on the passenger side while it blows cold air itself on the driver’s side? That’s a very weird situation to be in and there is no way you can, especially the person sitting on the passenger side, tolerate such a situation.

There are several causes that make AC blows hot air on passenger side while cold itself on the driver side. These will be discussed in detail in this article, so read on!

AC Blows Hot Air On Passenger Side: Why?

There are a few reasons why ac blows hot air on passenger side. If the air conditioning in your car is blowing hot air on one side and cold air on the other, there could be a simple fix, like adjusting the temperature or it could be time for you to replace a part like a temperature blend door actuator.

This can also be because of a faulty HVAC control module which can be further diagnosed with an advanced scan tool. Here are some common reasons why your car’s AC blows hot air on one side and cold on another.

1. Temperature Settings Adjusted Differently

Are you sure you checked if the temperature settings are set differently for the passenger side and driver’s side? Sometimes the temperatures on the AC can be set differently which creates the situation, AC blows hot air on passenger side while cold or normally on the driver’s side. This can be remedied by just adjusting the temperature on the cold side or vice versa to your desired degree.

2. HVAC Control Module Program Needs To Reset

You can sometimes interrupt the HVAC or Heating, Ventilation, and Air Conditioning control module’s program after disconnecting the battery. Their function is to conduct a self-test to find the blend door actuator’s location. If such a situation happens, the module might read inaccurate data, leading to an inaccurate temperature and requiring recalibration.

You can reset the HVAC or recalibrate it by disconnecting the negative terminal of the battery for about 5 minutes. After this, turn the key on and do not touch any of the HVAC controls. This will hopefully reset the module and the condition, ac blows hot air on passenger side.

3. Faulty Blend Door Actuator

The temperature blend door actuator or blend door actuator or vent mode actuator can break or malfunction with time. The blend door is faulty if the HVAC control module commands it to set in a particular position but it fails to comply. This leads to situations like the temperature blowing hotter on the passenger’s side. You can identify a faulty blend door actuator by noticing a clicking noise coming from worn or broken internal parts. A faulty blend door actuator can also be identified with a powerful scan tool.

4. Mechanical Problem With Vent Door

Sometimes mechanical issues with the vent door can cause your AC to blow warm air on the passenger side. Sometimes the vent doors can be jammed or stuck or can have issues being controlled.

5. Temperature Sensor Not Working

If the temperature sensor of your car is not working, your vehicle will have a hard time picking up particular information and thus can cause your car’s AC to blow hot air on the passenger side. A fault temperature sensor can affect the way the temperature settings work.

6. Head Unit Or HVAC Controls Not Working

The head unit or HVAC controls, if they are not working, can blow hot air on the passenger side. Commands may work intermittently or not at all, making it difficult to control the temperature settings.

7. Electrical Issues

Your car’s AC works with the help of electricity. Therefore there are a lot of electrical components behind the working of the air conditioner. However, damage in any of these components can damage the working of the AC and it can either cause it to blow warm air as a whole or just on one side. Tracking down such an issue can be very difficult and you may need the help of a mechanic in such a situation.

How To Diagnose A Faulty Blend Door Actuator?

Even though there are many reasons why AC blows hot air on passenger side, the most common reason is a faulty blend door actuator. An advanced scan tool can be used to diagnose a bad blend door actuator. The scan tool will let you know if the blend door actuator is in a different position than commanded. If there is a problem with adjustments and commands, difficulty moving, the blend door actuator is faulty and must be replaced. If it is also making a clicking noise, that is a sign for you to replace the actuator.

Where Is The Blend Door Actuator Located?

The temperature blend door actuator is usually located on the driver’s side of the vehicle, just above the accelerator pedal and on the side of the HVAC box. It is usually screwed in with an electrical connector on the corresponding driver or passenger side of the vehicle. In some other vehicles, it is seen that the blend door actuator is located above or below the heater box, otherwise known as the HVAC box.

Can I Replace The Blend Actuator On My Own?

Replacing or repairing the blend actuator is not a very hard task. It can be done on your own if you follow the below steps well.

  • Remove the glove box.
  • Remove the Temperature Door Actuator
  • Disconnect the wiring harness of the temperature door actuator now
  • Then remove the two 7/32 inch bolts from the actuator
  • Pull off the actuator
  • Now install the Temperature Door Actuator
  • Then go on and line up the shaft with the new actuator
  • Push the actuator into place
  • Insert the two 7/32 inch bolts into the actuator carefully
  • Connect the actuator wiring harness
  • Now test the actuator by moving the temperature control and watching the actuator
  • Install the Glove Box


It would be very uncomfortable to you as a passenger when your or someone’s car you are travelling on is blowing hot air on you, especially if it’s summertime. Nothing can be more uncomfortable than this when you are travelling in a car. This article has discussed the most common reasons why AC blows hot air on the passenger side while it blows normally cold air on the driver’s side. Hope you found the article helpful!

Leave a Comment