Chevrolet 2000 Tahoe Owner's Manual page 124

Mirrors
Inside Day/Night Rearview Mirror
Pull the tab under the mirror toward you to reduce glare
from headlamps behind you after dark. Push the tab
away from you for normal daytime operation.
2-48
Electrochromic Inside Rearview Mirror
with Compass (If Equipped)
When on, an electrochromic mirror automatically dims
to the proper level to minimize glare from lights behind
you after dark.
The mirror also includes an eight
the upper right corner of the mirror face. When on, the
compass automatically calibrates as the vehicle is driven.
-
point compass display in