LED taillight bulbs

So I finally got some clear taillights for my ranger, and got some LED 3157 lamps for the back. when I put one of the bulbs in to test it, it blew a fuse twice. Now, i dont know if anybody else has had this problem or not, but I dont know where to get decent bulbs. Did it blow because I only had one bulb in, or do the LED's run under different load?