“The chrysler guy sent me a diagram with “wiring information for my model’s lighting system” is that it?”
Without see it I really couldn’t say, but I would assume it is.
“That diagram says that the power feed wire leads from the relay/fuse panel straight to the light assembly connection.”
If that is actually true, the issue may be with the relay/fuse panel. A loose or corroided contact perhaps.
What you could do is remove one fuse / relay at a time and look at the contact pins down inside the fuse box to see if there is any corrosion.
Worse case you may have a faulty fuse box ( not unheard of with this make ).
At that point I would suggest taking it to a qualified tech to confirm that possiblity before dropping a load of $$$ for a replacement fuse box.