1968 Buick Skylark Front Turn Signals and Parking Lights Pr

This 68 skylark is is extremely excellent condition, it only has 38k original miles. Everthing is clean and unmolested including the wiring. The front turn signals won't come on, I have replaced the bulbs. If I turn on one of the turn signals, both front turn signals blink (both rear lights work correctly). Also both the turn signal indicators on the dash blink. The emergency lights work fine. I replaced both blinker switches under the dash (for emergency and turn signals). I bought a new turn signal switch for inside the steering column, disconnected the old one and hooked up the new one, the same problem, so it's not that. I have been tracing ground problems, haven't found solution yet. The turn signals housings, connectors and wiring all look very good, this car was parked in an estate garage for 13 years after the original owner died. Nothing appears bad, or chewed up.
Thanks,
Dennis