Cadillac 1994 Eldorado Owners Literature page 132

MIRRORS
Automatic Inside And Outside Rearview Mirrors
Your Cadillac is
equipped with an
automatic
electrochromic
inside rearview
mirror.
-
This mirror automatically changes to reduce glare from headlights behind
you. A photocell on the back of the mirror senses when it is becoming
dark outside. Another photocell built into the mirror surface senses the
headlights behind you.
L .
The mirror will darken gradually to reduce glare. This change may take
a
few seconds.