My rear turn signals don't work

They went out almost a year ago, but I didn’t care much since I rarely used them anyway. Anyhow, I only know of two bulbs for each light assembly in the rear, and all of those bulbs are working. IF there’s another light bulb in there, let me know. Anyhow, I guess a relay is bad, but I don’t know where that would be located. The front turn signals work, but flash very fast. I don’t care about that, but I need the rears to work. That’d cut some value off the car unless it’s fixed, IMHO. Anyhow, and help is appreciated.