At Wit's End

I'm usually pretty good at automotive electric but this one has really got me. I had no tail light on the right (P) side, everything else was good. I pulled the light and found the tail light wire was spliced into the harness and had come apart. Made a temporary repair and all was good. Yesterday I made the correct repair to the line (solder/heat shrink) and now, 4 ways good, brake and tail lights good, directionals good BUT when I step on the brake with the directional (left) on, the flash moves from the amber directional section to the red brake light section and the dash indicator hyperflashes like a bulb is burned out (I guess it senses that the amber section bulb is not working). Right side works as intended. I pulled the left connector apart and cleaned the terminals, ran an extra ground line all without any change. The right light and connector haven't been touched. It seems to me like a ground issue but my test light/multimeter indicates that there is a ground.
Anybody out there got any idea what's going on? Where can I find a tail light schematic? Thanks in advance for any help you can give.
2001 Tacoma SR5
4cyl/Automatic

 

There is a sticky thread at the top of the 1st gen section where you'll be able to find a digital copy of the Factory Service Manual (FSM). It will have the wiring diagrams for all the circuits in the truck. It might help you to know that most of the systems are ground switching.