[ossiblue]

Greg,

As you've discovered, the wiring to the turn light is secured in a loom that has very little chance for vibration or abrasion, that's why it's a puzzle where the fault is. Look very closely all along the loom, where possible, searching for any signs of cuts, abrasions, or heat/melting. I suspect if you ran a long jump wire from the fuse to the turn light as RoninLB suggests, it would work correctly without blowing a fuse. It is so unlikely that a car of your vintage would have a ground fault in a secured loom that I still suspect some mechanical damage or touching of uninsulated wires. Keep up the hunt, and keep us up to date.