Formally called the Chevrolet C/K, C/K is a series of trucks manufactured by General Motors and marketed under the Chevrolet and GMC brands. The C/K line includes pickup trucks, medium-duty, and heavy trucks.
@edaya something is drawing to many amps. When your say your ac knob, are you referring to your fan speed. It could be the fan motor or a bad resistor pack. Let us know the exact year and model of your P.U. so we can look at the wiring diagram.