Symptom: Turn signal lamp is off. Diagnosis procedures
Electric horn
does not sound
or sounds
hoarse.
Separate connectors
of turn signal lamp,
measure and check
with an ohmmeter if
turn signal lamp switch
works on faulty side.
Yes
No
Battery is
low.
All the turn signal lamps on
one side are not on.
Yes
Yes
Yes
No
No
No
Turn signal lamp is still on after short circuit.
Turn signal lamp is not on.
Some of the turn signal lamps on one
side is not on.
All the turn signal lamps are not on.
Take down the turn signal lamp
cover and check if the bulb is burnt.
Replace
turn signal
lamp bulb.
Measure voltage between
power line contact of lamp
holder and the ground with a
voltmeter.
No voltage display
No voltage display
Grounding wire of lamp
holder is of poor
contact or bulb of turn
signal lamp is badly
contacted with lamp
holder.
Power line to
the lamp
holder is
broken.
Take down the turn signal lamp
cover and check if the bulb is burnt.
Replace
turn signal
lamp bulb.
Power line on
the troubled side
is broken or
grounding wire
of lamp holder is
poorly contacted.
Inner contact
of turn signal
lamp is poorly
contacted.
Press horn button and
check
Electric horn
sounds loudly
Power supply from
battery is normal.
Take down the turn signal
lamp cover and check if
the bulb is burnt.
Slide turn signal lamp switch and short circuit it with a piece of
wire or a screwdriver two lugs of scintillator.
Replace turn signal lamp
bulb and check if regulator
works normally.
Turn signal lamp is still off after short circuit.