Toyota Prius Owner's Manual page 234

2-2. Instrument cluster

Brightness of the instrument panel light
If the headlight switch is turned on while the surrounding area is dark, the
instrument panel lights will dim.
CAUTION

To prevent an accident
Instrument cluster
NOTICE

To prevent damage to the engine and its components
The engine may be overheating if the high coolant temperature warning light
comes on or flashes. In this case, immediately stop the vehicle in a safe
place, and check the engine after it has cooled completely. (P. 578)
234
PRIUS_OM_OM47A19E_(EE)
Do not place anything or attach a sticker
in front of the instrument cluster. The item
may obscure or obstruct the display, or
could reflect off the display, possibly
causing an accident.