Well, honey, the vacuum line on a 2003 Chevy Silverado 2500HD is typically located near the intake manifold or throttle body. You might want to grab a flashlight and get down and dirty under the hood to track it down. And remember, if in doubt, consult your vehicle's manual or a professional mechanic before you start yanking things apart.
Under the intake manifold.
the bolt pattern is 8 on 6.5"
The 2003 Chevrolet Silverado-2500HD has 16 valves.
The 2003 Chevrolet Silverado-2500HD has overhead valves (OHV).
The 2003 Chevrolet Silverado-2500HD is a gas-powered vehicle.
The 2003 Chevrolet Silverado-2500HD has a V8 engine.
The 2003 Chevrolet Silverado-2500HD has a 5-speed manual.
The height of the 2003 Chevrolet Silverado-2500HD is 6 ft. 4.2 in. (76.2 in.).
The 2003 Chevrolet Silverado-2500HD runs on regular unleaded.
The 2003 Chevrolet Silverado-2500HD's turning circle is 43.8 ft..
22 gal - shortbed 34 gal - longbed
The 2003 Chevrolet Silverado-2500HD has a 11 ft. 1 in. (133 in.) wheel base.