You may be hearing the fan clutch kick on, which is normal.
Same thing happened to my 2003, less then a year after I brought it. The AC unit was burned out a week later. Seems to be a problem with the KIA ac units, don't let them lie to you at the dealer about it being your fault!
Most likely the Blower Motor Resistor.
"Which fuse controls the fan for the ac on a 2006 Chevy silverado?"
Replace the HVAC resistor pack, it is defective.
The 2003 Chevrolet Silverado-1500 has a V6 engine.
The 2003 Chevrolet Silverado-1500 has 12 valves.
The 2003 Chevrolet Silverado-2500HD has 16 valves.
where is the fuse for heated driver seat on 2003 Chevy Silverado>
The 2003 Chevrolet Silverado-1500 has overhead valves (OHV).
The 2003 Chevrolet Silverado-2500HD has overhead valves (OHV).
The 2003 Chevrolet Silverado-1500 is a gas-powered vehicle.
The 2003 Chevrolet Silverado-2500HD is a gas-powered vehicle.