OK, I've spent half the day in the sun checking components and the
other half writing and reading emails to help the process. All have
been very helpful, quite an education.

Here's where I'm at:

The terminal 1 on the big connected is providing an intermittent 12v
with the flasher. So that's working.

If I take out the instrument cluster and put 12v+ to the #1 lead on
the circuit, and the ground on the ground of the blue foil circuit,
the turn signal LED lights up.

The terminal connection seems to be good.

So, if 12v is getting to a circuit, and the components of that
circuit are know to operate properly under 12V, what else could be
wrong?

In other words, if everything in the circuit is checking out right,
but my light doesn't flash, am I looking far enough back from the LED?

Could my flasher relay be putting out a weak or otherwise wrong
voltage/ground? Is it worth swapping one out? Can I use the on in my
90 for the test?

Thanks,

Jim