Kenny,
you'll need one on each side. get a variable resistor from radio shack 1 Ohm to 100 ohm or so. Place it in series on the positive side, make sure it's set to 1 ohm and turn on the directionals. Turn the variable resistor until it blinks at the speed you want. Then disconect and measure the resistance with your ohm meter. Then buy the resistor you need at radio shack 1/4 watt resistors should be fine.
