Voi-frickin,-la', problem solved!

Thanks to all those with great suggestions. Because of the (low) current at the turn signal socket, I was convinced the problem was somehow there and didn't look very far.

It was a bad ground. Not noticeably bad, of course, no crumbling corrosion or anything. I just went to the common ground in the engine compartment, directly beneath the coil, took it apart, cleaned it w/ baking soda and water, sanded to metal and sanded the connectors, greased with dielectric and reassembled. Voila!

Still weird, though. The negative side of the socket tested 0 ohms to the chrome-plated bumper ... and why did the right side work fine, don't they share a ground?

Thanks again for all who helped.

Ed Carroll