Chip is correct about needing a 3 terminal flasher if you have a pilot light in the dash. I have an aftermarket turn signal switch that came on my truck when I got it and when doing some testing on the bench, I discovered that the flasher didn't work at all. Being the engineer that I am, I pulled the cover off the flasher to see what was wrong, and saw that the internal workings use extremely small gauge wire. So it's entirely possible that the wire to the pilot bulb has broken inside the flasher. A replacement 6V flasher should fix you up for not a lot of money. I got mine from NAPA.
