The ac malfunctions like when we turn it on all controls are in the proper setting . The ac will start to blow cold air ,then abruptly change to heated air and will not return to cold air again. What could be our problem? And how can we repair it?

>Moved from Forum Help<

The ac malfunctions like when we turn it on all controls are in the proper setting . The ac will start to blow cold air ,then abruptly change to heated air and will not return to cold air again. what could be our problem? and how can we repair it?

>Moved from Forum Help<
The problem with your truck, Diane, is likely either the HVAC control head is faulty and sending erronious signals, or the electric motor that controls the air mix door is binding or restricted and is defaulting to one setting.
Pinppoint diagnosis is necessary for your truck.