How do i fix the sensor that controls the blowing of the air conditioner and fan.

The most common cause of this is that you have a stuck air temperature control blend door, this can be a motor actuator issue or a jammed door or both (common). To replace both parts you will need to completely remove the dash from the car to access the blend door.

As per your problem mentioned.There are few solved help links to troubleshoot these problems.Go through the list and Click the link below:----
Air conditioner blows air but not cold air http://repairhelpcenter.blogspot.in/2012/07/air-conditioner-blows-air-but-not-cold.html

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Car overheats and Air blows hot at idle? http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

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Heater blows cold? http://schematicsdiagram.blogspot.in/2012/02/heater-blows-cold.html

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Heat blows cold on drivers side and hot on passenger side? http://schematicsdiagram.blogspot.com/2011/12/heat-blows-cold-on-drivers-side-and-hot.html---------- Hot air on the driver's side vents only? http://repairhelpcenter.blogspot.com/2012/01/hot-air-on-drivers-side-vents-only.html

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2005 Chrysler PT Cruiser: A/C Blows Warm? http://whoisbyme.blogspot.in/2012/06/2005-chrysler-pt-cruiser-ac-blows-warm.html

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1992 Toyota Camry: A/C Control light Flashing and A/C not Blowing Cold? http://technoanswers.blogspot.in/2012/04/1992-toyota-camry-ac-control-light.html

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No heat, blower blows only cold? http://technoanswers.blogspot.in/2012/02/no-heatblower-blows-only-cold.html

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These will help.
Thanks.

My air conditioner on my Buick has a full charge of Freon and when it is hot out I don't get the cooling power in the cabin as I have it on low switch so when I put the switch on the high the Air doesn't change to cool the interior on high. I had the Freon tested and it still doesn't work properly and I wonder if there is a sensor that doesn't allow the system to cool properly?

blend motors

sounds to me u need to have it recharrged

possibl ac compressor clutch problem,cooling fan at rad not working so ac goes into high press mode and turns off(so it doesn,t blow system apart,built in safety)not enough r134 in system(low charge)

You have a fan temp sensor located on the engine block that controls when fan turns on or off.

bad blower motor or resisiter.

You have a loose of vacum to he AC controls. The different doors that direct air to dash floor vent ect. are vacuum operated, the vacuum source is the engine.