Flasher problem - 1998 Ford Explorer

My turn signal/hazard lights went out two days ago. I asked for advice and was told to replace the flasher. I bought one at Pep Boys(the guy at the desk gave me the one) and replaced the one in the truck. I'm assuming I replaced the correct part (it was located under the panel under the steering wheel in a little box with other square shaped plugs). THe new flasher was slightly larger than the old one (just the outer part, it plugged in fine), and I couldn't quite get the box closed, but when I turned the car on, I just heard a buzzing sound coming out from that location every 3 seconds or so, and the signal lights still didn't come on. Was this the correct part to replace? Should I buy an original part from the Ford dealership? Should I be looking at another part? Any advice would be appreciated.