Please clarify. By AC do you mean the AC compressor, or just the HVAC system blower motor?
1) If you mean the AC compressor, is the button OFF on the control module? If it's on, then the AC will ALWAYS cycle on and off if the temp is above 35 degrees, for dehumidifying the air.
2) If you mean the blower motor, that's a possible failure mode of the resistor pack (if you have the analog heater controls) or the blower motor speed control module (if you have the digital controls.
Clarify what your problem is and what kind of control module you use, and we can advise more.
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