I'm back on this issue, but fortunately for you I am reporting on the problem after the fix.
My signals just stopped working... no lights anywhere. I went nuts with a multimeter, and I found wiring, switches and bulbs were OK. The last place I checked, which should have been my first was the flasher unit. Really, I didn't know how to check it, besides replacinging it, and ta-da... the signals work.
The reason I bring this up is that the $8 EL13 electronic flasher I used only lasted 300 miles. I have it mounted inside an old radiator hose, which is zip tied to the battery box. The radiator hose is inteneded to help dampen vibrations, and of course the battery box is also rubber mounted. I think the flasher died due to vibration.
Is there a heavy duty (vibration resistant) flasher out there that you're using? Auto Zone had a few that were labeled "heavy duty" but I think that meant amperage load... not sure.