How to fix heat control flaps on your car
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Nothing is more frustrating than turning on your heater during hose cold winter drives and getting nothing. Problems with your heating arise from different causes. Take a look at our guide to issues with heat control in your car including heat control flaps and how you can fix them.

The HVAC Heating Ventilation and air conditioning cleans cools, regulates, ventilates and dehumidifies air within your cabinet. Although there different manufacturers equip their vehicles with different type of systems, the basic functioning principle is the same.

We are going to discuss some of the most popular problems associated with jeep heating e.g. the heat control flaps and walk you through how you can fix these issues.

HVAC system

Let’s review some major components of HVAC systems and their role in proper heating and ventilation.


Also known as the heater core, this is the part on the HVAC system that looks like compact radiators. It is constructed will aluminum or in some cars brass tubing that is responsible for carrying the coolant in and out of the system. This parts function is basically to perform heating and defrosting action within the system.


This is another important part of your heating system that is useful in cooling liquids. The thermostat is responsible for restricting or allowing movement of the coolant from engine to radiator or heating core.

It is important that you maintain the thermostat in prime working conditions otherwise your engine will suffer several consequences including overheating, under heating an overall engine performance.

Blower fan

The blower motor or blower fan is the element that blows air through this system and to the compartments in your cabin. This part along with the heater core are often on the passenger side of your vehicle, allowing them to operate how much heat can enter the cabin and at what speed it will enter.

Blend doors actuator

 fix heat control flaps on your car

The blend door is fixed within your vehicle’s air conditioning system. These actuators are small electric motors that move the vent doors to control the temperature inside the vehicle’s cabin.

They direct warm or cool air into different passages to maintain desired temperatures in the passenger side.  When the driver selects warm air, the door moves to divert all heated air into the car’s cabin.

As the car gets warmer, the door reduces the amount of heat entering the cabin. If the driver needs cool air, the blend door shuts so that no heated air enters the passenger area.

Simply put, the actuator is responsible for the mechanical opening and shutting of these doors. It shifts the blend door automatically when the temperature control is altered.

Popular heat control flap Jeep issue

One of the more popular issues among Jeep owners with heat control flaps is the control acting up. A bad control will equal trouble properly opening the flaps. The most common cause for this issue is often an electrical issue somewhere. This could include disconnection or a burnt IC chip.

There is usually an electric actuator for the mode change doors, which when faulty will trigger issues with controlling the flaps. In some Jeeps, there is a control arm under the driver side on the AC unit connected to an actuator.

If that control arm is not connected to the blend door it won’t change modes, making it seem like you have a control issue. Luckily, you can check it visually to see if it is connected or not.

Alternatively, you may use a DTC scanning device to read the codes in your system and check for any ACT control problems. This may be helpful in pinpointing the issue with your controls.

Common causes of other issues with heat control in your car

Problems in your car heater often arise when there’s an issue with the system. Examples of instances when less than optimum conditions trigger faulty heater functions include the following.

Clogged cabin heat filter and heater controls

This is a common problem with older cars. As your vehicle ages, the controls and heater parts gradually build up residues and other gunk.

When trouble shooting your vehicle for heating control issues, you should suspect blockages when everything else seems in order but your heating continues to misbehave.

Additionally, build up on controls will cause restrictions in the system and make it difficult for you to efficiently operate your heater system.

Dirty or low levels of coolant

Low levels of coolant inside the system will automatically cripple proper heater functions. The same is true if you have dirty coolant. Dirty coolant has a caramel like color unlike clean coolant that is a bright green or red.  In addition to improper function, dirty coolant easily becomes electrolyzed and acidic in nature. At this state, it can start to corrode engine or other system parts.

Role of coolant in heating your car

The coolant plays the essential role of taking heat away from the engine and its components, ensuring this part functions properly.  Many engines cannot withstand excessive heat and require it taken away for prime function. This combination of distilled water and ethylene glycol aka Antifreeze is elemental for excess heat absorption within the engine block that if otherwise left alone could result in engine overhaul.

Tips on flushing your jeep system

coolant flushed

Usually, you are advised to have your coolant flushed every 50K miles or so. However, if you get your fluids checked and the coolant doesn’t look too great, then a flush won’t be the worst thing. To flush out your jeep:

  • Begin with a cool motor before you flush out your coolant system. You will need a bottle radiator flush which you pour into the radiator and seal the cap. The good news is, you can find the instructions on the bottle of radiator flush.
  • Proceed to turn on the engine and do as the bottle says to do.
  • Next, let the engine cool down and then safely remove the radiator cap and drain out the flush from the system through the radiator drain.
  • Lastly, flush the system with water until the water draining from the system is clean or clear.

Heater core problems

Because of the role the heater core in your HVAC system, many people associate their heater problems with this component. Heater core difficulties may imply coolant is not travelling properly through the system. Most of the time, heater core issues will lead to your HVAC system blowing cool air into the system instead of blowing warm air.

Some other signs of a failing heater caused by a problematic heater core include: a fruity smell, rapid depletion of coolant levels, an overheating engine, and fog inside your car.

Faulty thermostat

When your thermostat gauge does not shift correctly with temperature change then you might have a faulty thermostat. Luckily, these are usually pretty easy and inexpensive to fix. However, with a faulty thermostat, your car won’t receive signals that your engine is warm. Leaving your engine with a lot of residual heat from engine operation, which could be harmful if left alone.

Broken Blower fan

Like the name suggests, the blower fans job is to blow a wave hot air from the core and distribute it to your heat vents. With a broken fan, you will not feel any air coming through the vents. A bad motor or faulty switch could render your blower fan broken and you might even notice no air coming through into the cabin.

Troubleshooting heating issues on your jeep

Step 1 – Find the cause

Diagnosis is usually among the most important steps in fixing most car issues. Once you have the cause down, then finding a permanent solution becomes easier. Inspecting the system for wear and tear will help locate any torn, split or leaking parts. More often than naught, the issues with your heating are due to a leak or an obstruction. Low heat delivery to your Jeep cabin is common especially when you have obstruction and damage.

Step 2 – Check your fluids

Fluids play an important role in proper systems operations. This includes the coolant and all other fluids involved in heat control. Check your reservoirs for appropriate fluid levels and for contamination. If either of these happens, then you may experience various difficulties with your system.

Step 3 – Repair broken parts

Next, is to replace all the broken and worn parts. Whether blown, broken or worn, these malfunctioning parts cripple proper functioning of parts of your HVAC system if not all of it. The only way to remedy such kinds of problems is to have them fixed or replaced.

It depends on what part of your heating system is problematic. To repair the heater core on the Jeep wrangler for example will cost you between 620 to approximately 790 dollars inclusive of labor and parts purchase cost. This price will vary depending on where you live or if you own a different kind of Jeep.

A cooling system flush on the other hand could cost you a maximum 200 dollars. Again, these prices will vary depending on your model and your location or even the shop you frequent to have your car repaired.

Final Word

Problematic heating is not only bad for you during cold weather but also bad for your engine. There are many possible causes of issues with heating in your Jeep. It is important to always properly diagnose these issues before hand so you can efficiently solve them.