First thing, I've done a bunch of reading and searching and at this point I'm hoping someone else has had a similar problem and can narrow the options down.  The problem, rear lights are possessed.  Headlights work, high and low beams.  Front turn signals work, left and right.  Rear right turn signals work.  Rear left work but are dim and turn off when the lights are turned on.  Also all left rear bulbs flash including side marker when turn signal is turned on.  Right side flashes fine except the parking light turns off when turn signal is turned on.  I've taken apart both the multi switch and the turn signal switch to clean the terminals.  I've read maybe the hazard switch can cause this?  Is this the case and how can I test this?  I've tried adding grounds with no change.  Ideas?

More info, I took a test light to the back of the turn signals with and this is what I found.  Right turn signal on, WR, GB on turn signal side and GB in middle all have power.  Left turn, WB, GR and GB in middle all have power. Lights on no turn signals, WR, GY, WB, GR all have power.  Lights on and fight turn signal on, WB, GR spark when touching test light that is grounded to the chassis.