Checking The Lighting System - Yamaha YFM250RX 2008 Service Manual

EBS01069
3. Wiring
• Check the entire lighting system's wiring.
Refer to "CIRCUIT DIAGRAM".
• Is the lighting system's wiring properly con-
nected and without defects?
YES
Check the condition
of each of the light-
ing system's circuits.
Refer to "CHECK-
ING THE LIGHT-
ING SYSTEM".
EBS01070

CHECKING THE LIGHTING SYSTEM

1. The headlights fail to come on.
1. Headlight bulb and socket
• Check the headlight bulb and socket for
continuity.
Refer to "CHECKING THE BULBS AND
BULB SOCKETS".
• Are the headlight bulb and socket OK?
YES
NO
Properly connect or
repair the lighting
system's wiring.
NO
Replace the head-
light bulb, socket or
both.
7-29
LIGHTING SYSTEM
2. Voltage
• Connect the pocket tester (AC 20 V) to the
headlight couplers as shown.
When the light switch is set to "LO"
When the light switch is set to "HI"
Headlight coupler (wire harness side)
Headlight
Positive tester probe →
Negative tester probe → black
• Set the main switch to "ON".
• Start the engine.
• Set the light switch to "LO" or "HI".
• Measure the voltage (AC 12 V) of yellow
or green on the headlight coupler (wire
harness side).
• Is the voltage within specification?
YES
This circuit is OK.
ELEC
yellow or green
NO
Replace the rectifier/
regulator.