Thanks for all the good advice gentlemen. The OEM rear light wire I ordered just came in. Here is a picture of the old one on the left and the newer one on the right. Notice that the old one lacks a reverse lights blade for some strange reason.
I was going to remove the steering wheel to remove the old turn switch to have it replaced, but since we moved I cannot find my steering wheel puller. Still looking...
After exhausting going over the wiring and diagrams for several months, I guess the problem MUST be in the turn switch. Updates later...
