Bulb Check
The bulb check function resides in the BCM. Every time the ignition switchtransitions from ACC to ON, an instrument cluster bulb check will occur for a calibrated amount of time for specified indicators. The bulb check will override the OFF state of the affected indicators. The BCM will determine which indicators to bulb check by looking at an EEPROM table. Every Serial Peripheral Interface (SPI) indicator has a bit in the EEPROM table. The gauges will WOW during a bulb check. A WOW occurs when all of the gauge indicators are moved at the same time. If there is an indicator lit before the WOW, the indicator will remain lit after this function has concluded.