Reserve Lighting System; Headlight Does Not Function; "Head" Indicator Bulb Does Not Glow - Yamaha XS650SE Shop Manual

B. Reserve lighting system
1. Description:
The reserve lighting system has two
functions: (1) It notifies the rider that
one of the head lamp filaments is inopera-
tive, and (2) it switches current from the
inoperative filament to the remaining
functional filament.
The system is connected to the headlight
circuit only. The reserve lighting system
unit is located under the fuel tank.
L