TPB,
I might be flogging a dead horse here. You haven't said what turn signal setup you have...what brand and model it is.
Signal-Stat models 900, 901 and 910 are all common to these old truck and they all use a three prong flasher.
I have tried to find a picture of the guts of one of these units to see if it could be a funky bulb deal inside or a mechanical problem, but alas, no soap on the pix.
I'm not a wizard on these things but all the dope shows a three prong flasher, and the third prong is what works the little pilot lights to signal a left or right turn in your column mounted switch.
Cletis has dug around with these and written a Tech-Tip...maybe he will take pity on me and jump in with the true poop!
Stuart
