Yamaha RS90K Manuel D'atelier page 665

Check the tail/brake light bulb(s).
NO CONTINUITY
OK
Check the main fuse, ignition fuse, and signal fuse.
Refer to "FUSE INSPECTION" in CHAPTER 2.
FAULTY
OK
Check the battery.
Refer to "BATTERY INSPECTION" in CHAPTER 2.
OUT OF SPECIFICATION
OK
Check the stator coil.
Refer to "CHARGING SYSTEM".
OUT OF SPECIFICATION
OK
Check the main switch.
Refer to "CIRCUIT DIAGRAM".
FAULTY
OK
Check the load control relay.
FAULTY
OK
Check the lighting system's wiring.
Refer to "CIRCUIT DIAGRAM".
FAULTY
OK
Correct the connection and/or replace the rectifier/
regulator and/or ignitor unit.
LIGHTING SYSTEM
TAIL LIGHT DOES NOT COME ON.
Replace the tail/brake light bulb(s).
Replace the main fuse, ignition fuse, and/or signal
fuse.
Replace and/or charge the battery.
Refer to "BATTERY INSPECTION" in CHAPTER
2.
Replace the stator coil assembly.
Replace the main switch.
Replace the load control relay.
Properly connect or repair the lighting system's
wiring.
8-22
– +
ELEC