Meter Illumination does not Dim at Night: Description
If the dimmer switch is turned to TAIL, HEAD or AUTO, the main body ECU sends a TAIL relay signal, panel light illumination signal, panel relay signal, and TAIL cancel OFF signal to the combination meter. Then the meter and accessory meter become dim.
HINT:
TAIL cancel switch: When the headlights are illuminated and the TAIL cancel switch is turned ON, the meter does not dim.