The most common cause of the air conditioner in a 2004 Ford Ranger to run even when the control is set to the vent position and no AC is desired is a faulty blend door actuator. The blend door actuator controls the flow of air from the heating and air conditioning system to the interior of the vehicle. When the blend door actuator is faulty, it can cause the air conditioner to run even when it is not turned on.
Here are some other potential causes of the air conditioner running when it is not turned on:
* Faulty temperature control switch
* Faulty wiring
* Faulty climate control module
To diagnose the cause of the problem, you will need to take your vehicle to a qualified mechanic. The mechanic will be able to use diagnostic equipment to identify the faulty part and repair it.
