To be certain, you should:
* Consult your owner's manual: This is the best resource for precise location information.
* Search online for a wiring diagram: A wiring diagram specific to your year and model Silverado will show the location of the flasher relay. Many websites dedicated to vehicle repair offer these diagrams (sometimes for a fee).
* Visually inspect the area under the dash: Since it's near the steering column, you may be able to locate it by careful observation.
Remember to disconnect the negative battery terminal before working with any electrical components in your vehicle to prevent short circuits or accidental damage.