Tail light circuit board

What symptoms do you get when you have a defective circuit board in a tail light? I'm still trying to find the source of a short.
Symptoms:
The left turn signal won't flash- just stays on after an initial "click". I
replaced the flasher fuse with no change.
The dashboard lights will flash when the right turn signal flashing.
If I disconnect the rear taillight wiring, there is no change in the left turn signal (dash light still stays on when you turn the left signal on) but the right tail light now acts appropriately as a no load circuit (rapid flashing of signal).
Any suggestions? Maybe two different problems? Thanks for all the help!
Tim Bluff City, TN
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Rapid flashing indicates a shorted bulb. No flashing indicates, i guess, no load. It could be a broken wire in the turn signal lever.
Cheers

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.