Turn Signal Cancel? (Not the springs!)

[1968_K20_4x4]

Hey all,

Trying to fix my turn signal. It cancels properly when making a right turn, but will not cancel when turning left. I had read that it could be the little round springs but when I checked they were both there and working fine. What do I try next? Im thinking replace my turn signal canceling cam... mine has slight wear marks in the plastic and I am wondering if it has worn down enough to cause it to stop working properly. Any other suggestions? The truck is a 1968 and does NOT have tilt steering. Thanks!