3 wires coming out of turn signal switch? Using relays? What switch is that? Better post pics of switch and that diagram. You take a good photos of the diagram and switch and relays and use attachment manager to add to your post.
"I gutted the wiring and rear lights, installed single bulb medium duty truck lights"
You don't say how many bulbs each side in rear?
Anxious to learn this trick.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn