Auto A/C Controls...Blend and Mode Door Actuators

Modern cars and light trucks use small electronic actuators to control the temperature and mode selections. These electronic controls replaced the vacuum operated actuators, used through the 80's and into the 90's, to pivot the blend door and the mode door into the selected position. Unlike the vacuum controls that are either "ON" or "OFF", the electronic actuator is adjustable to an infinite number of positions.With the introduction of the infinitely adjustable "Electronic Actuator" it became possible to have computer controlled climate control as well as dual zone climate control. 

The electronic actuator uses a reversible electric motor that is attached to the blend or mode door pivot point by gears inside the actuator. By varying the voltage supplied to the actuator motor, the door is moved to the requested position. In vehicles with Computerized Climate Control Systems, the blend door actuator is controlled by an on board computer that adjusts the temperature output to achieve the exact temperature the operator requests...and then keeps adjusting the blend door actuator to maintain that temperature when it is achieved. 

Symptoms of a faulty actuator include a mode door that seems to be stuck in the defrost position or a blend door that seems to be stuck in heat or cool position. Occasionally this is also accompanied by an audible clicking or thumping sound from behind the dash. Replacement of either the blend door actuator or the mode door actuator may require the removal of the dash.

Kool Kar Specializes in  Auto Air Conditioning! With Over 30 Years in The Auto Repair Industry...We have the skills and Technology to Repair your  Car or Light Truck...Kool Kar is the A/C Authority in Texas.
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YOU MIGHT ASK,  "WHY IS MY FLOORBOARD WET ON THE PASSENGER SIDE."  If you do not have a water leak due to a leaking windshield, my money is on two possible causes.

The first thing you need to look at...does it smell like antifreeze? If so there's a very good chance you have a heater core that's leaking.  If it is just water, with no funny smell, you most likely have condensation leaking from your car's evaporator.

Here is the deal...your Air Conditioning evaporator will condense water and it must drain off.  Normally the condensation drains from the evaporator to the bottom of the evaporator case where there is a drain, that carries the water to the outside of the vehicle.  If this drain becomes plugged for any reason, the water has no where to go, and will drain directly into the floorboard.

Kool Kar Is The A/C Authority In Texas...Call for all your Auto Air Conditioning Needs.


AUTO A/C LEAKS ARE ONE OF THE MOST COMMON PROBLEMS WE FIND WITH TODAY'S CARS AND LIGHT TRUCKS...and at times, they can be one of the most difficult to detect. There are two types of leaks that can be present on vehicle air conditioning.

First there are static leaks...these are leaks that leak when the A/C is not running.  Static leaks, leak all the time no matter what the condition.  They are not sensitive to hot or cold or barometric pressure most of the time.  However this is not always the case. Every now and then we see static leaks that will be sensitive to temperature change, or barometric pressure variations.

Then there are Dynamic leaks.  These are leaks that only leak when the system is running.  Which means the system must be at operating pressures for the leak to appear.  This type of leak can be more difficult to find because with the engine running, the condenser fan and engine fan blows away the refrigerant making it extremely difficult to fine with electronic leak detection equipment.  I recommend using tracer dye for this type leak...It will show up over a period of time and you should be able to find the leak.

A/C hoses are always a good place to start...check hose crimps and all connections before you do anything else.

For additional information on A/C problems, or many other issues with your vehicle, visit is at

Kool Kar Auto Repair is the A/C Specialist in Tarrant and Parker counties. Give us a call today at 817-270-2549 for all your automotive needs.

Auto A/C

Auto A/C is one of the top three most sought after accessories on today's cars and light trucks.  After all it's really not an accessory, it in fact is a necessity, especially if you live in one of the really hot parts of the country like Texas for example. No one will buy a vehicle today unless the A/C is in proper working order.

But when that Air conditioning does not perform properly, it can be a real drag, and get you hot under the collar (among other places). Sometimes an A/C system will slowly begin to decline and you may not even notice it at first.  After it begins to blow hot air you certainty will notice it. 

I would like to give you some tips that something may be up with your cars air conditioning.

1.  If you hear your A/C compressor begin to make noise, it probably will give you real problems, sooner or later, usually sooner.

2.  If the air no longer comes out the vents as forceful as it once did.

3.  If the air comes out the wrong vents when you turn the mode selector.

4.  If you notice it's taking longer to cool down the vehicle than it use to.

5.  If you have water draining in the passenger floorboard. 

6.  If you notice this constant clicking sound under the hood.  It could be your compressor cycling rapidly.  Which usually means low refrigerant. 

7.  If you smell a bad odor when you turn your a/c system on.

8.  Trying to install refrigerant in your own car is a bad idea.  Why? because you have no idea how much refrigerant is already in your system.  Adding to much refrigerant to your system can be worse than not enough.  Why? because you can over stress your systems compressor with to much refrigerant, causing it not to cool properly and possibly damaging the compressor or other components. Did you know your systems charge is so important, that as little as a half  ounce to much or to little refrigerant in some systems, can cause a cooling issue. That's why I say charging with cans is a bad idea. Again there is  no way to tell how much refrigerant is in a system without professional charging and recycling equipment.

Kool Kar Auto Repair is your number one source for all your Auto Air Conditioning needs. After all we are the A/C authority in Texas for a reason. 615 S.E. Parkway Azle Tx 76020 817-270-2549