To find it, you'll likely need to:
1. Consult your owner's manual: This is the best place to start. The manual should have a diagram showing the location of the fuse box and relays.
2. Look in the fuse box under the dash: Many Silverado models have the flasher relay in a fuse block under the dash. The fuse block often has a cover that lifts up, revealing the fuses and relays. Often, relays are larger than fuses.
3. Look along the wiring harness near the steering column: If it's not in the fuse box, it might be clipped or taped to the wiring harness in this area.
Important Note: If you're unsure about working with electrical components, it's best to take your Silverado to a qualified mechanic. Improperly handling electrical parts can lead to damage.