The left turn signal on column won't engage and " click in". Light works and no trouble with right hand turn. What's the problem ?

 

The canceling cam probably bit the dust. You're probably going to have to pull the steering wheel and lock plate to replace it.

 

+1.

Junkyard part, or you can buy one new at the corner parts store.

Not hard to change out, but the steering lock plate is annoying on a '69 and later if you don't have the tool (I'm too cheap to buy the tool...).

- Eric

 

Actually, the more common problem is that the cancelling spring breaks. You can get replacements from Dorman Products (P/N 49312).

 

Are you sure, Joe? He said that the switch wouldn't click into the "on" position in one direction, not that it wouldn't cancel.
I believe that in this case, the detent spring has gone (cracked switch body), thus preventing it from clicking in, but still allowing the contacts to turn the light on.

Easy enough to see whether the cancel spring is lying in the bottom when he pulls the wheel anyway...

- Eric

 

That's why I didn't go for the spring.

 

Pulled the wheel and it's a broken cancelling cam. Thanks to all for the excellent advice !