[rocketraider]

Autronic Eyes/Guide-Matics couldn't deal with reflective highway signs. That's why they were discontinued in 1970, on everything but Cadillacs. Caddys located the eye in the grille so theirs weren't quite as vulnerable to sign reflection. Even though dash-mounted units' sensitivity could be adjusted, reflective signs would still send them crazy.

You may ask why the other Divisions didn't simply move the eye to the grille. It had become a slow selling option by 1966 and was generally dealer-installed after then.