Turn signals on a 68 coup no work but flashers do

Although the hazards work fine, the signals stopped working a month back and I know the switch in the column had issues because I had to manually turn them off, when they did worked. All four corners flash when the hazards are on, so bulbs are good.

So

(1) I replaced the switch unit in the column. I checked and double check the wiring and pin positions and all match
(2) changed out both flasher units, and tried the one for the hazards in the turn signal position and the hazards still work but no turn signal.
(3) The plug for the turn sign flasher unit is getting power. I used a volt meter and checked with the ignition on and the turn signal switch turned to both right and left side.
(4) I replaced all the fused even though they all seemed good.

Any thoughts would be helpful.

Thanking everyone in advance.

Stephen