Heat on Passenger Side, Cold on Driver Side - What's Wrong?

The car climate system has been developing greatly within the past years. New technologies and super-sensitive electronics helped car manufacturers create wonderful automatic systems that can do unbelievable things. In modern vehicles, each person can set the needed temperature and travel in comfort. But things go bad when something is not working properly.

Today, we'll tell you why there can be heat on the passenger's side and cold on the driver's side. We will cover all possible reasons and will show you the solutions to this situation. Of course, the reasons may vary from one car to another and we won't be able to cover every possible malfunction that can lead to this. But we'll try to tell you about all the common issues.

Here's what we'll cover today:

• Why can your climate system split two sides of the car?
• What are the possible reasons for heat on the passenger's side and cold on the driver's side?
• Why should it bother you much?
• What to do with this problem?

Let's get started!

Why does your climate control split two sides?

Well, climate control in most budget-friendly cars is just the AC that you have to set by yourself. You choose the temperature, then you choose the fan speed and after that, you change these two factors to achieve the needed temperature level.

If you have a more expensive vehicle, you are likely to enjoy automatic climate control. It allows you to just set the needed temperature and then the electronics will automatically adjust all the needed factors to make sure you have the needed temperature inside your vehicle.

In even more expensive and modern cars, you will have the so-called dual-zone climate control system. It's when the driver and the passenger may choose the needed temperature for their zones.

Sorry for such a long introduction, but you need to know this so that we could answer your question. So, here's why climate control may split two zones and provide them with different temperatures:

1. You simply have the dual-zone climate control system

In this case, you should check the settings. Sometimes, we just don't notice how we or someone else change those settings. Something may have happened and the vehicle set the new settings as default.

Just look at the climate control system screen and check the temperature. The type of settings you will need to change depends on the model of your car. But, in most cases, it's all about just pushing the button that sets the temperature several times and adjusting the climate control settings to what you need.

2. Broken sensors in climate control

Dual-zone climate control systems are generally very reliable and never require any maintenance or repair. But sometimes, you will need to deal with sensor issues. Your settings may be OK but the sensor may send the wrong information to the control module. The module will give wrong commands and the system will blow the air with the wrong temperature into the car.

To check the sensors, you will need the OBD II scanner and some skills on how to use it. If you have a dual-zone climate control system and one side blows cold air while the other blows hot, the problem is most likely with the sensors. Locating and fixing the issue is possible with the help of professionals.

3. Blocked air inlets or pipes

One more issue that is very possible in some vehicles is the blockage in the pipes of the air ventilation system. The blockage can cause hot or cold air to stop blowing into some parts of the system. As the result, one side of the vehicle will be only cold or only hot.

The blockage can be caused by some objects, long-time deposits, dust, insects, etc. This is mostly possible after the vehicle has been standing still in your garage or just outside for a long period of time.

Also, the air inlets in your car interior may be blocked. In this case, the climate control system may be working just fine, but the inlet will not allow the air to come into a certain part of your car's interior. That's why one part will remain cold while the other will be heated or vice versa depending on the season.

4. Stuck plastic partitions (blend doors) in the system

The climate control system consists of plastic pipes and partitions. When you press some buttons on the control panel, these partitions move in correspondent positions to allow or disallow airflow to certain parts of the system. Also, this works for cold and hot air - a couple of partitions open or close warm airflow. Once one of these partitions gets stuck and doesn't move to the needed place, the system will fail.

It may sound like an easy problem with an easy fix. But in most cases, you will need to take apart the whole front panel of your vehicle to repair this. And yes, this is going to cost you a lot in labor bills because it takes some time.

5. Blend door actuators

Another issue that is very common for older vehicles with the automatic climate control system is a failed blend door actuator. These actuators make blend doors (the plastic partitions we were talking about before) to move in needed positions. Once these actuators fail, the doors can't move and just freeze in a certain position. This will cause hot air on one side of the vehicle and cold air on the other side.

If the problem is in the actuators, you are lucky enough. They are easy to diagnose because they send codes to the ECU. This means you can diagnose them with the help of a scanner. Replacing them will anyway be pretty tough, so you will have to pay for labor.

Why should you be bothered by this problem?

The issue with hot air on one side of the car and cold air on another side may seem like a minor problem. But in a lot of cases, this will mean that you can't use the vehicle. This will be not only uncomfortable but also unsafe for your health.

If the driver's side air inlets blow in cold air, you are going to have a couple of problems:

• obviously, you will be cold, so there is nothing good, especially at a cold time of the year;
• you will not be able to set your climate control to the needed temperature;
• you are risking health problems because of cold airflow;
• you will not be able to drive long hours because of the discomfort;
• you may even catch a cold or flu if you already have some virus but the immune system still deals with it.

So, you should solve the problem because it will not allow you to use the car. The situation may seem not that serious but it is and you should know about it. We don't tend to think a lot about the importance of climate control systems in our vehicles until we lose the possibility to use them.

Also, if the car AC smells weird, you can read our article about the AC smelling like nail polish remover.

What should you do to deal with this problem?

First of all, you should check all the positions on the list of problems we've written about before. Check the easiest possible issues like the wrong settings. If this doesn't help, you will need some professional help. Just make sure you let someone experienced diagnose your vehicle.

Here are the steps you should take in this situation:

• find a car shop or a dealer that will be able to repair any issue of the listed above;
• ask a professional to diagnose the vehicle with the scanner first and find possible issues;
• also, ask the experienced mechanic to try and find the problem just by driving your vehicle for several minutes;
• if the issue is found, just have the needed parts replaced and enjoy driving;
• if the problem is not found, change the shop and try again;
• be prepared that you will have to pay for labor quite a lot.

The more expensive the car, the more you will pay for repair. Modern vehicles have a lot of issues with climate control systems and some of these issues may cost you thousands to repair them. Even simple parts like the blend door actuator may cost you several hundred dollars for some models.

So, a good diagnosis is a key to success in this case.

Final thoughts

We are sure you will not be glad to drive a vehicle that blows in too cold or too hot air from one side of the climate system. If you have this problem, address it now while it's not causing a lot of problems. If you need to drive a couple of hundred miles in such a car, you may feel problems with your health and you will obviously experience a lot of discomfort.

Diagnosing and repairing the issues that cause the climate control system to fail is not really easy and fast. You should go to professionals who have the needed equipment and enough skills to locate and repair the problem.