Cecil, The 46 is like my 41 I think, are you using 2 tail lamps or 4? If you are using 2 tail lamps you are going to have to add 2 lamps or do what I have done (or am going to do).
Origionaly these trucks didn't have any turn signals. They were added to the system as aftermarket devises. The normal installation of these turn signal systems required the addition of more lights on the rear and front or modification of the front by rewiring the sockets to accept double element bulbs and adding lamps to the rear.
The truck origional had only 1 lamp on the rear. It had 2 single element bulbs. One bulb was stop lamp and the other was park lamp.
What I am about to do (and it will work) is add a rt. side stop lamp (aftermarket also with 2 single element bulbs) and install a device used fortrailer lights on vehicles with seperate turn signal and stop lamp bulbs. Instead of hooking it up for trailer lamps I will hook it up before the tail lamps and it will seperate the turn and stop lamps.

I didn't do it, no one saw me do it, you can't prove anything! "Bart Simpson"