I had the same problem Mark.
I didn't think it was a good idea to wire the turn signals to the key switch because if I need to leave the truck by the side of the road with the emergency flashers on, I don't want to have to leave the key in the ignition!
I isolated the switch unit from the column with some rubber and re-wired the unit so the indicator bulb would only come on when the lights were flashing.
A whole lot easier fix that Larry Kephart came up with is to just use the #550 flasher made for Alfa Romeo, Austin, BMW, Fiat, Jaquar, Mercedes-Benz, MG, Peugeot, Porsche, Renault, Rolls-Royce, Triumph and Yugo. I understand that does the trick.
