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Q: Mode control on air conditioning does not work.

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EverytI me i turn on my car and turn on the air, it only comes out of the defrost vents. Even if I changet it to other modesites it stays there.

My car has 70860 miles.
My car has an automatic transmission.

A: Your car comes equipped with a possible man...

Your car comes equipped with a possible manual and an automatic heating and A/C system. The automatic system is a set it and forget it system. You set the desired temperature and the car will adjust itself accordingly. The manual system requires you to adjust the temperature as needed. The two systems use all the same components with the exception of the temperature control module. Specifically the automatic system uses a module to control the climate in your passenger compartment.

Both systems have what is known as a mode door actuator. This is an electric motor that moves the mode door under your dash. The mode door actuator is the most common failure in most HVAC systems. The HVAC module in the automatic system tells the mode door what position to be in. If it has failed, it will not send a signal to the mode door actuator. The manual system has a mode position switch that will also send a signal to the mode door actuator. If it has failed, the result will be the same.

The previously listed components are all there is to the mode control in a typical HVAC system. Aside from them, you will need to check all the fuses. Be sure to do this first. If you need help with any of this, a certified mechanic, such as one from YourMechanic can come to your car's location to diagnose your air vents system and make the necessary repairs.

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