Farmer, the Light Switch Rod (inside the Steering Shaft in the Column) may be bent. They can be bent when trying to remove them. Especially on closed cars without lowering the steering column. They can be straightened but requires a lot of patience.
I had the same problem, It's a classic on Mod A s. While your switch rod may be bent, if the problem has just begun, it may be a small brass bearing/bushing that is at the top of the rod/column. #5050 in Brattons, pg 21 $1.95
Terry
It could be buildup of crud in the bottom of the steering column and the light rod fighting against the crud. You can clean it out with a .38 caliber bore brush and lacquer thinner. You have to take the steering box apart to do this. This is what I found in mine.