glennj3, In the hope that it may prove helpful in figuring out your wiring and lighting control issues, attached below is a copy of a "Grote" turn signal device wiring instructions and diagram. The wiring diagram has color codes marked for each wire, which should help you trace your individual light fixtures wiring.
The diagram and instructions provided is based on your picture above of the "Grote" switch shown in your truck. Perhaps fellow Bolter bartamos can use the info and his offered help to guide through further inspection, testing and repair of your lighting?
