Replaced turn signal switch, but now it won't cancel?

I replaced the turn signal switch and it works, but it does not "cancel" when returning the steering wheel to center. 1989 Ford E 150 van, 5.0 liter, w/tilt and a/c. Part is new, ordered from RockAuto.com for $100. Switch has a center ring which rotates with the steering wheel. There's a spring loaded post on the center ring that engages a slot in the rear of the steering wheel. With the wheel off, I can engage the turn signal, then turn the center ring by hand and it will cancel the turn signal, as expected. When I install the steering wheel I can look through the slot next to the Hazard Warning switch and verify that the post engages the back of the steering wheel, and that the ring rotates with the wheel when I turn it. With the wheel off, the cancel works. With the wheel on, it does not. Any ideas? Thanks
Added (1). What I called the center ring is actually called the "cam" in mechanics parlance.

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