The meter CPU receives auto dimmer signals from the main body ECU via the CAN communication lines (CAN No. 1 Bus). When the meter CPU receives an auto dimmer signal, it dims the meter illumination. The main body ECU determines whether it is daytime, twilight, or nighttime based on the waveform transmitted from the automatic light control sensor. If the main body ECU determines that it is daytime, the ECU does not send auto dimmer signals. Therefore, the meter illumination (warning and indicator lights) will not dim even if the driver accidentally turns the light control switch to the TAIL or HEAD position in daytime.
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