To find the correct wire, you should:
* Find your truck's VIN: This is crucial for getting the correct wiring diagram.
* Use a wiring diagram: You can often find these online through sites specializing in automotive repair information (some are subscription-based, others may offer free limited access), or at a local auto parts store. They'll be far more reliable than any generalized color information.
* Use a multimeter: Once you have a diagram, a multimeter can help you verify the wire is carrying power only when the ignition switch is in the "run" position (not "accessory" or "start"). This is the definitive way to identify the ignition wire.
Trying to identify the wire solely by color is unreliable and could lead to incorrect connections and potentially damage to your vehicle's electrical system. Always use a wiring diagram and a multimeter for this kind of work.