I installed the pins in the 2 holes in the back, but still does not cancel turn signal after a turn is made. Have any other ideas, or suggestions? This is installed on a stock 1976 steering column with default internals. Adapter mates up well and the horn works - just not the cancel pins.

Assuming it was cancelling before, bend/pry the pins away from the center, to adjust the contact with the cancel cam. If you signals did not cancel before, check that your cancel cam is good, and not broken. You can look at our part #2854, for reference. If it is broken, then the pins may have nothing to catch, to cancel. That is a common issue as well.