To be certain, you should:
1. Consult your owner's manual: This is the best source for the specific location in your vehicle.
2. Check your fuse box diagrams: The fuse box cover usually has a diagram showing the location of relays and fuses. The flasher relay will be labeled as such, or possibly as a "turn signal relay."
3. Search online for a 2000 Ford Ranger fuse box diagram: Many websites provide diagrams specific to the year and model. These can help you locate the flasher relay visually.
Remember to turn off the ignition before searching for the flasher relay.