FIGURE. Flash-to-pass feature added to the headlight circuit.
Many steering column-mounted dimmer switches have an additional feature called “flash to pass.” This circuit illuminates the high-beam headlights even with the headlight switch in the OFF or PARK position. In this illustration, battery voltage is supplied to terminal B1 of the headlight switch and on to the dimmer switch. Battery voltage is available to the dimmer switch through this wire in both the OFF and PARK positions of the headlight switch. When the driver activates the flash-to-pass feature, the contacts in the dimmer switch complete the circuit to the high-beam filaments.